This might be easier in safe mode, but you might be able to do it in Normal mode as well.
You say you can run Task Manager. If you can, run a command prompt (I think its File > Run ... and then type
When the Command Prompt box opens type
at the prompt. After some time the scan will finish and report if any issues have been found.
Restart your computer and run a full virus check as soon as you can. Also run a disk check to make sure your drive is not damaged. Personally I would not trust this drive if no viruses are found. Back up all your importand data and replace the drive if you can.
Let me know how you get on.
I really appreciate thank you messages as a payment for solving issues :o)