Run this anti-malware application.http://www.majorgeeks.com/Malwarebytes_Anti-Malware_d5756.html
It will scan and produce a log which you can read through to see if the hidden folder and it's contents have been deleted.
Be sure to run the full scan and remove everything it finds.
You haven't stated your operating system so it's a bit difficult to advise beyond the scanner. The scanner will work with Windows NT/2000/XP/2003 Server/Vista.
If you need help with the log post it here.