Virus??

Dont have any ideas...........better do online scan at these sites.
*www.bitdefender.com/scan8/ie.html
*housecall.trendmicro.com/
*www.pandasoftware.com/products/ActiveScan.htm
*www.kaspersky.com/virusscanner

I think that is enough..if u need more online scan..post here.

When you delete a file in Windows NT Explorer or My Computer, the file is stored in the Recycle Bin. The file remains in the Recycle Bin until you empty the Recycle Bin or restore the file.

The Recycler folder is used only on NTFS partitions. The Recycler folder contains a Recycle Bin for each user that logs on to the computer, sorted by their security identifier (SID).

*support.microsoft.com/kb/171694

i think its a virus dude. Scan with mcafee, it will safely delete this virus.

fair enuff do scan ur pc with ur mcafee in safe mode, just to be sure.
2 b doubly sure get ur hjt logfile auto-analyside for malware at www.hijackthis.de

There is no single recycle bin. What windows does is, it creates a Recycled folder in the root of every drive. Whatever you delete in a drive goes to the Recycled folder in that particular drive. Inside that folder many subfolders are created with the the names like you mentioned: S-1-5-21-725345543-2000478354-839522115-1006 and so on...
Windows keeps track of it from a single recycle bin from the desktop. Its that simple.
If you are worried with such folders, then just hide the hidden folders and its gone...!

i doubt if those are viruses ?

ur antivirus shld be able to catch them.

Do u installed new softwares?
they might be the culprit..

just post your HijackThis log file