Help! Thousands of files on my PC that I did not download ! file?

I'm really hoping that you guys can help me. Whenever I use the windows search feature, sometimes I'll put in a random single letter just to view all the files on my pc. Upon doing so, I've discovered that probably thousands of .avi files are on my pc, all with porno titles...I haven't tried to open any to see what they are. Anyway, under the "Folder" Column it reads " !(C:\Users\Blackhawk\) ". Also, the date these files were created was a date that I was not even home or using my pc.

When I try to delete the files, it says that " this file is no longer located in C:\users\blackhawl\! " I have run Norton Protection Center's scan, as well as adaware, and spybot. None have detected any malware.

Can you guys tell me what this is, how it got on my computer, and how to get rid of these unwanted files? This seems very strange to me and I would love to know what happened.

I have also since dowloaded and use Zonealarm. Also, I'm running widows vista

Thanks in advance!

Help! Thousands of files on my PC that I did not download ! file?virus scan

You have a virus that creates itself, but then moves its location before a scanner detects it. So it is invisible.

If there are no noticable effects, i would ignore it... these viruses and trojan horses usually give you pop ups, which are blocked by Norton.