OS

[manishdhar]

HP 15 R202 LAPTOP FORMATTED AND TEMPORARILY INSTALLED WIN 10 FOR EMERGENCY WORK.NOW I AM UNABLE TO GET BACK TO MY LEGAL WINDOWS AS PRESENT WINDOW 10 WANTS 25 DIGIT PROD KEY. BUT MY PROD KEY IS 20 CHARACTER

[WAWood]

@manishdhar 

You can't "get back" to your original key because that will only work with the original HP OEM version of Windows that came preloaded on the PC.  Windows product keys are OS-version specific.  If you installed a retail version, something you got from Microsoft, you have to use a Retail product key.  An OEM product key, which is what is encoded into your PC, will not work with that version.

[Paul_Tikkanen]

Hi, @manishdhar 

The product specs for your notebook indicate that it came from HP with W8.1 64 bit.

What we don't know is whether or not HP installed the plain W8.1 64 bit or the W8.1 Single Language OS.

HP 15-r202tx Notebook PC Product Specifications | HP® Customer Support

So what you need to do first is this...run the free Showkey Plus utility that I zipped up and attached below.

That will show you the original version of W8.1 that was installed on your PC.

If it does not indicate Single Language, then download the plain W8.1 64 bit ISO file from the link below.

That would be the first file listed under the drop down menu.

Download Windows 8.1 Disc Image (ISO File) (microsoft.com)

If the report does indicate W8.1 single language, then download the plain W8.1 Single Language ISO file from the link above.

That would be the last one listed on the drop down list.

Use the Microsoft tool that I zipped up and attached below that you will need to transfer the ISO file to a USB flash drive or DVD so that it is bootable, or you can use a different utility such as Rufus.

If you downloaded the right ISO file, Windows will not ask for a product key when you boot from the media and go to install W8.1.

After W8.1 has completed installing, you can install the drivers and available software from your notebook's support page.

HP Notebook - 15-r202tx Software and Driver Downloads | HP® Customer Support