So the key issue seems to be the NVidia driver. Which one are you using now?
For the time being
- please check if your virtual memory/swap space is set correctly (system controlled)
- you could also specify Max Performance in Advanced System Settings, this switches off Cleartype text, but you can select it afterwards
- and maybe your system is doing a virus scan or something like that, you can check that in the task manager (after Ctrl-Alt - Del)
Please come back if I am going to fast and need to explain more.
Henk