Uninstall Pre-installed Windows 10 and install Windows 8.1

[SudipMajhi]

My HP Notebook comes with pre-installed Windows 10 Home edition. I want to install Windows 8.1 and I have the original product key of that version. Can I install that on my own? If I install, will it void the warranty?
Thank you.

[Huffer]

It will not. I can understand rolling back to Windows 7 but we do not get too many questions about a Windows 10 to 8.1 downgrade. Still , the heart wants what the heart wants. 

Posted drivers are for Windows 10 and 7 only so you will have to dig around for 8.1 drivers. @Paul_Tikkanen I am sure can help with that. Post back for any more help. 

[Paul_Tikkanen]

Hi:

You will be able to use the W8.1 x64 drivers and software from the 15t-ac000 on your model, except the BIOS and firmware files.

http://support.hp.com/us-en/drivers/selfservice/HP-15-ac000-Notebook-PC-series/7771404/model/8381866

[Ananya24]

Step 1: Get software and drivers

It is advisable to get all available recommended software and driver updates while the computer is still using Windows 8.

1. Go to the HP Customer Care Web site ( http://www.hp.com/support ), select Software and Drivers, and enter your computer model number. Download and save the Windows 8/8.1 hardware drivers and software files to your hard drive.

   NOTE: If there is a Windows 8.1 operating system listed in the drop down menu, the model computer is supported.

2. Copy the downloaded files to CD/DVD or a USB storage device for use after installing Windows 8.1.

Step 2: Create Recovery discs and back up your important files

If you have not already done so, create a set of Windows 8 system recovery discs. If a problem occurs during the upgrade process, you can use recovery discs to return your computer back to its original software configuration. To create your personal set of recovery discs, see Creating Recovery Discs or Saving a Recovery Image to a USB Flash Drive .

You can use Microsoft Backup and Restore Center or Microsoft Windows Easy Transfer to back up your Windows files and transfer them to Windows 8.1.

If you want to backup your files using other software, you must first verify that it is compatible with Windows 8.1 before using it – This may require you to read the documentation that came with the backup software in the box, or you may need to visit the software vendor’s website. You will also need a copy of the software's installation files on a USB drive or disc.

Do not use backup software that is not compatible with Windows 8.1! If you are unsure as to whether or not your backup software is compatible with Windows 8.1, HP advises that you use Microsoft Backup and Restore Center or Microsoft Windows Easy Transfer.

When finished, verify that the backup was successful and that you can access your files.

Step 3: Disable Acceleration in Intel Rapid Storage

Some HP computers are configured with high-speed mSATA solid state drives in addition to the primary hard drive. The mSATA cache drive enables faster boot times and boosts the hard drive performance of the computer. Prior to performing a Clean Installation you must disable the cache drive acceleration in the Intel Rapid Storage Technology interface. After the Clean Installation you will need to install Intel Rapid Storage Technology and re-enable acceleration for the mSATA cache drive.

Determine if your computer has an mSATA cache drive:

1. In Windows 8 Start screen click type Intel Rapid Storage Technology and click Intel Rapid Storage Technology in the results list.

   NOTE: If Intel Rapid Storage Technology is not installed on your computer then you do not have an mSATA cache drive and should continue to the Install Windows 8.1 section.

2. In the Storage System View, computers configured with an mSATA cache drive display a square labeled 'cache.' If the Storage System View displays a cache drive then your computer has an mSATA cache drive installed. Continue to the next step: Disable Acceleration in Intel Rapid Storage.

   Computer configured WITH mSATA cache drive

   Computer NOT configured with mSATA cache drive

   Figure 1: Storage System View with mSATA cache drive

   

   Figure 2: Storage System View with mSATA cache drive and FFS partition

   

   Figure 3: Storage System View with a primary hard drive and no mSATA cache drive

   

Disable Acceleration in Intel Rapid Storage Technology

If your computer is configured with an mSATA cache drive, use the following instructions to prepare it for the Windows 8.1 installation.

1. In Windows 8 Start screen click type Intel Rapid Storage Technology and click Intel Rapid Storage Technology in the results list.

2. Click the Accelerate button at the top of the window and click Disable Acceleration.

   Figure 4: Disable acceleration button

   

3. Click Yes on the Disable Acceleration warning window.

   Figure 5: Disable acceleration warning

   

4. Click Reset to available next to Usage Cache device.

   Figure 6: Reset cache to available

   

5. Click Yes when the Reset Cache to Available warning appears.

   Figure 7: Reset Cache to Available warning

   

6. Close the Intel Rapid Storage Technology program and continue to the next step.

Things to expect during installation of Windows 8.1

• Interrupting the installation - The installation can be stopped and restarted at certain predefined points. When restarting the computer, a set of prompts allow you to either: Continue where you were, or Start Over.

• UAC security - The Microsoft User Account Control Settings displays a prompt and requires you to verify that you want the listed program to make changes in your computer. This prevents a malware or a virus from trying to install software.

  If prompted, Do you want to allow the following program to make changes to this computer? and the Program's Name is listed as Microsoft Windows and Verified Publisher as Microsoft Corporation, click Yes to allow the action.

• Choose a User Name and Password - By default Windows 8.1 is designed to seamlessly integrate your new computer into the Internet or Cloud with other social media and devices using a Microsoft connected user account; such as Microsoft LiveID, Instant Messenger, Gmail, or AOL mail account.

  • Local Account - You can enter a unique user name and password that is valid only on this local computer to keep this computer as an independent device that is not linked to other devices. You can still manually connect to the Cloud to share files later.

  • Microsoft Account - If you use your Microsoft connected user account to logon, this computer automatically links into all the other mobile devices and user information you have stored on all your social networking accounts.

• Allow multiple restarts - The computer will restart multiple times during the installation process. You can either remove the installation DVD during the restart, or ignore the prompt to Press any key to boot from the CD or DVD....

Perform a Clean (custom) installation using a DVD or USB flash drive

If you bought Windows 8.1 on DVD or created a DVD or USB flash drive when you purchased and downloaded Windows 8.1, follow these steps to perform a Clean (custom) installation.

1. Connect the computer to an AC power supply.

2. Turn on your PC so that Windows starts normally, insert the Windows 8.1 DVD or USB flash drive, and then shut down your PC.

3. If you have Internet, connect the computer to the Internet using either an Ethernet cable (Wired NIC), or turn wireless button On (Wireless LAN).

4. Turn on the computer.

5. When prompted to Press any key to boot from CD or DVD, press Enter.

6. On the Install Windows page, enter your language and other preferences, and then click Next.

7. On the Please read the license terms page, if you accept the license terms, click I accept the license terms, and then click Next.

8. On the Which type of installation do you want? page, click Custom.

9. On the Where do you want to install Windows? page, click Drive options (advanced).

   To continue, use one of the following actions to install Windows on a hard drive partition:

   • Install onto an existing partition: Simply select the partition labeled as “OS” and click Next. Doing so, clears the data in the existing Windows OS partition to use with Windows 8. However, the other partitions may not be removed and will continue to use hard drive space.

   • Delete all partitions and install on one partition of maximum size (advanced): Select drive options to enable more options on the screen then select and delete all partitions in the list. Once all the partitions have been removed, you can create one new partition of maximum available size and format it. Once you have one partition and it is formatted, select this partition and click Next to continue.

   • Create more than one partition and install on one of them (advanced): Select drive options to enable more options on the screen and delete all partitions in the list. Once all the partitions have been removed, you can create new partitions of different sizes and format them. One of these partitions must be at least 20GB in size to allow for the installation of windows 8. Using this method allows you to set aside separate partitions of storage space to be used in Windows 8 as additional drive volumes (in File manager and Computer). Once you have one partition and it is formatted, select a partition that is 20GB or larger and click Next to continue.

   

10. When you've finished formatting, click Next.

11. Follow the instructions to finish installing Windows 8.1.

    NOTE: Make sure that you have your Windows 8.1 product key available when prompted.

Enable mSATA cache drive and acceleration (optional)

If your computer is configured with an mSATA cache drive, you should re-enable acceleration in the Intel Rapid Storage Technology settings to increase the performance of your PC. Use the following instructions to set up the drive for Windows 8.1.

1. Go to the HP Customer Care Web site ( http://www.hp.com/support ), select Software and Drivers, and enter your computer model number.

2. Select Windows 8.1 from the menu.

3. Download and install Intel Rapid Storage Technology (version 11.5.4.1001 or greater) from the Software and Drivers page.

4. After the software is installed, from the Windows 8.1 Start Screen type Intel Rapid Storage Technology and double-click the Intel Rapid Storage Technology icon.

   Figure 8: Intel Rapid Storage Technology in Windows 8.1

   

5. Click the Accelerate button and then click Enable acceleration.

   Figure 9: Enable acceleration in Intel Rapid Storage Technology

   

6. In the Enable Acceleration options, select Full disk capacity (up to 64 GB) and then select Enhanced mode. Click OK.

   Figure 10: Enable Acceleration options

   
7. Restart the computer.

Steps to take after upgrading to Windows 8.1

1. Connect to the Internet if your computer is not already connected.

2. Install updated video drivers - For the best possible experience, install the latest drivers for your computer. If you downloaded the drivers earlier, use the Windows 8.1 drivers stored on your CD/DVD or USB storage device.

   Go to the HP Customer Care Web site ( http://www.hp.com/support ), select Software and Drivers, and enter your computer's model number. Download and install the Windows 8.1 drivers for your computer.

3. Create a Windows Recovery Drive - Creating a Recovery Drive on DVD or a USB storage device can help resolve startup issues and restore Windows 8.1 if there are problems later.

   From the Windows 8.1 Charms bar, select Settings then Control Panel. Type recovery then click Create a recovery drive.

4. Restore backup files - If you upgraded to Windows 8.1 using a Clean Installation you can restore the files that you backed up before the installation. See Restoring Files from Backup for instructions.

5. If the computer had a Windows 7 or Windows 8 Recovery Partition and Recovery Manager, the Windows 8.1 installation removed them. If you want to restore the original operating system after upgrading you must use the Recovery media you created before upgrading, obtain recovery media from HP or by purchasing a retail version of the desired Windows operating system.

Thanks

Ananya24