Hi,
If you suspect that there might be some elements of virus on the computer then you may
run a full computer scan with Microsoft Safety Scanner to make sure that the computer is free from virus. Once this is done, restart the computer and check if you are
able to install the updates.
Microsoft Safety Scanner: http://www.microsoft.com/security/scanner/en-us/default.aspx
Note: There could be a loss of data while performing a scan using Microsoft safety scanner to eliminate virus if any.
Further, to check the health of the system files, you may run the SFC scan.
I would suggest you to perform SFC scan and check if that helps. The SFC /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions.
For more information how to do SFC/ scan, please follow this link:
http://support.microsoft.com/kb/929833
Once this is done, restart the computer and try to install any one pending Windows Update to check the status.
Article for reference:
Updates: frequently asked questions:
http://windows.microsoft.com/en-us/windows/updates-faq#1TC=windows-7
Reply with the status of the issue and we will be glad to offer our assistance.