Virus eating up my disk space! Decompression bomb??

Hi!
Few days ago something started to happen with my computer. Before I had ca. 20GB free space on my Local disk C:. Yesterday i noticed that the free disk space was under 10GB and the meter that shows you how much free space you have was red, and the computer was sooo sloooowww. I taught i have installed to much programs and that so i deleted 1 GB, and then my free memory was over 10GB again, the meter was blue and the computer run as usually. But a bit later the computer went slow again and i checked the free disk space and it was under 10GB again!!?? WTF!!?? I had only used internet and not downloaded anything! I deleted 1 GB again, and after en while there was again under 10GB. I scanned the whole computer with Avast, and it found two files that were unable to scan and i tried to delete it but avast says: “Error occured duing file deleting. The file is a decompression bomb”.

How do I delete the files to get my computer run properly again???

The file location for the first file is:
C:\Users\Seppo\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\X08IK8TG\Windows6.0-KB936330-XG4-wave0[1].exe[Embedded_I#0003998d]

and for the second file it is:
C:\Users\Seppo\AppData\Local\Microsoft\Windows\Temporary Internet Files\Low\Content.IE5\NCU32K2A\Windows6.0-KB936330-XG4-wave0[1].exe[Embedded_I#0003998d]

I USE WINDOWS VISTA HOME EDITION.

PLEASE HELP ME FAST! MY COMPUTER LOOSES MORE FREE MEMORY ALL THE TIME!

//Sami

Decompression bomb is not, in most cases, a virus. Decompression bombs are supercompressed large files.

If you want to clear them up, you may:

(1) Press Windows key+R
(2) Type: cleanmgr
(3) Check Temporary Internet Files [you may also check other options]
(4) Click OK

or download ccleaner or glary utilities ;D

Slowness has nothing to do with decompression bombs. That could be cleaned as posted before.
Use TreeSize freeware to check which folders/files are using the disk space. Before deleting anything, ask :wink:
http://www.jam-software.com/freeware/index.shtml#treesize?cp=UpdateService&cp_kwd=TreeSizeFree_EN