Open any internal page such as Computer, Control Panel or Documents and go to Tools on the top Menu Bar, then go to Folder Options and click the View tab
Look for the 'Hidden Files and Folders' item, and check the item 'View Hidden Files and Folders' if not already checked and click Apply and OK
Go to C:\ProgramData\McAfee\VirusScan\Quarantine in Vista/Windows 7/Windows 8 or
For XP the folder is found at: C:\Documents & Settings\All Users\ApplicationData\McAfee\Virusscan
If your drive letter is another one than C: then alter the above accordingly.
Under normal circumstances those folders would be empty most of the time anyway.