You can install windows 7 on your PC. You will need a bootable disk or pendrive with windows 7 (64-bit) and product key. You can buy from Microsoft or for lot cheaper online.
You will need to disable secure boot in Bios and enable legacy boot. Now change the boot order so that the computer boots from USB drive or DVD. Install Windows 7, delete all partitions and install in unallocated space.
After installation you can get all your drivers from HP site here: