Click: My Computer/"C"/Program Files/McAfee Folder. Look for the virus vault. Open the vault, select all files and delete.
Its is always a good idea to now delete everything from your Recycle Bin.
If above doesn't work then try this:
C:\Documents and Settings\All Users\Application Data\McAfee\VirusScan\Quarantine\ and delete the contents. (Not folder pls)
'Select All' then click Delete, Clear Recycle Bin
Shift+Delete would bypass the Recycle Bin.