Use the Microsoft tool that I zipped up and attached below that you will need to transfer the ISO file to a DVD or USB flash drive so that it is bootable, or you can use a different utility such as Rufus for this purpose.
Since the recovery partition is basically useless space, you may want to delete it during the W8.1 installation process to free up more space for your programs and files.
After W8.1 has completed installing, you can install the drivers and available software from your PC's support page.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".