There must be something in my pc that changes the executable files (OS = WinXP - SP2).

e.g.

1)I run Spybot S&D and it gives me a message stating that the exe has changed and I should check for viruses (I do check with ClamWin and Norton but no luck)
2)When downloading a zip file from the net and try to open it using the windows compressed folder utility, it mentions that one of the executables inside the compressed file is changed and the zip file is corrupt. I disregard the message and use 7-zip to uncompress the file and try to execute the just extracted setup.exe , Installshield checks the crc and reports that the file is altered/corrupt and I should re-download.


When trying to network scan the machine using McAfee , it only scans 3-4 files and stops, Spybot S&D finds nothing, Lavasoft Ad-Aware finds nothing, Spyware Doctor finds nothing, but I know there is something in there.

There is a Sygate Personal Firewall installed, no windows shares and no internet gaming or P2P, only browsing to specific sites.

A guess might be that an older machine in the same network which uses Win95 (and is very old) might have something that the recent antivirus/antispyware programs cannot find.

Any suggestions?

do you get corrupt zip message with every archive or only some?