Virus in Comp!!

I'm running Windows 7. Though the computer runs just fine, without issuing any errors, i am sure i have a virus on it, for the following reasons

1. I am unable to open cmd - when i run it, it opens for 2 seconds and then just closes.
2. I am unable to open msconfig - same as above
3. i cannot install any antivirus - my 60 day trial of mcafee expired a few days ago, and i tried reinstalling avg. again when i open the setup, it runs for a min or so, and then just shuts down!!
4. I have been unsuccessful in opening windows in safe mode too. windows start up just hangs when i try.

need i say more?

I am getting a 25% CPU usage when nothing is running on my computer, and i think thts a bit too much.

Even though i can't see any visible changes in the performance of the system, i really want to get rid of the virus!!

Help me pls...

ok, thanks...i think thts exactly what i'll do. was just hoping there was another way. :) thanks a ton.

I dont have an antivirus at the moment

Petey7 said:

Lets see what we can do. What happens when you try to open task manager (ctrl+shift+esc)? Have you tried MalwareBytes? Have you tried to do a system restore to a time before the symptoms became apparent? Do you have a restore disc or partition?

I do not see anything unusual in the task manager... However, i am new to 7 and don't exactly what tasks should be running and what not.

I do have a restore disc.