Q: When I did a full system scan with avast anti virus, for some files it gave the result as "Unable to scan:The file is a decompression bomb." Now I want to ask what should I do next? I tried to delete those files but failed
A: Decompression bombs are malware - a file that has been repeatedly compressed by various zip programs, so a small file might unpack to several Gigs. This wastes your disk space, hangs your machine if it uses it all up, and takes a huge amount of time to unpack. It is safe to put them into Winzip or WinRar, but only to see how big the expanded size will be. Be VERY careful not to hit the "extract" button. To get rid of it, first set a System Restore point to be on the safe side. Then go into Safe mode, and try to delete the files manually. (Get the names from the Avast! log file). You may need to change hidden or read-only properties to be able to remove them. Don't leave them in the recycle bin!.