The reasons can be plenty. I gave the solution to my case which had nothing to do with the drivers. I have updated drivers on my Ubuntu install as well and it works well.
Here were the symptoms in my case
1. Firefox Crash - You are simply looking at the screen and it goes away
2. Nvidia drivers crash
3. Intermittent Mouse hang ups, scroll hang ups and then resuming automatically
4. Observed slow speed of the system
I scanned and removed the malware with some added practices of my own like completely emptying ~temp folder from Ubuntu install, as windows could not empty it and then removing the startup entry as well like stated earlier.
You can try though!