I like windows 7 and windows 10 a lot more than windows 8.1 but if you didn't run windows disc cleanup and delete the approx 24GB of 8.1 that remains on your hard drive after updating to windows 10 you can use system restore to go back to windows 8.1
Then you can find the windows 10 drivers for your GPU or get a new one.
You can install free classic shell and get a windows 7 style start menu in windows 8.1 or windows 10. When it's installed in 10 you can click back and forth between the win 10 start menu or the classic shell win7 start menu.
Classic Shell - Start menu and other Windows enhancements
Download Classic Shell 4.2.5 - FileHippo.com