Windows 8 Major Windows 8 issues. Crashing, blue screen, can't update to 8.1. Help Please!

So I have a Lenova Ideapad z710. It's a powerful gaming laptop, and came with Windows 8. There was tons of blue screens due to Nvidia crashing, and that seems to be sorted out.. But regardless, there's tons of freezing and crashing for no reason. And I tried updating to 8.1 not to long ago, through windows update. After it downloaded and tried to install, it said "software not compatible with this system" and reverted back to 8. And ever since than, its laggy and slow so terribly and I can't figure out why. First off why can't I update to 8.1? My specs are more than enough to handle it, and the device is updated quite frequently as my model is still pretty new. And there's no viruss on my system.. Anyways please help. I'm pretty good with computers, so if there's anything you wanna get me to try, just let me know, I should be able to follow instructions pretty easily.