Hector,Its probably a virus. May even be in system restore.
Try turning off system restore, this will purge system restore, then turn it back on and see if you disk space improved. To do so go to start>control panel>system>system restore tab>check the box beside "turn off system restore">apply>ok. Restart the computer and check your disk space. Turn system restore back on by unchecking the box>apply>ok.
If that didn't increase your disk space by a huge amount it could be something other than a virus.
Post a Hijack This log to help search for files containing any viruses. You can download Hijack This at this link http://www.tomcoyote.org/hjt/ then place it into a folder of it's on, such as C:\HJT, so that back up copies can be made and not clutter your desktop or other folders and the backup copies of deleted items can be easily located if needed.
Once saved double click HijackThis.exe, and press "Scan". When the scan is finished, the "Scan" button will change into a "Save Log" button.
Press that, save the log, Ctrl-A to Select All, and copy its contents into the text editor at this forum.
Do not fix anything yet unless you know what you are doing. This is a powerful tool that can crash the computer if used improperly.
