wow that's a tough question. Whilst it 'is' possible that a computer can be controlled by outside users hacking in, that would be an extreme case.

Try some of the online scans, such as 1. (viii) Microsoft Malicious Software Removal Tool listed here http://www.gnutellaforums.com/open-d...uld-aware.html

Or download & run the utilities listed in Step 3 in the above link. Such as Malicious Software Removal Tool for removal of Malware & the others listed.