I download a file and run it in my comp now all my security software are not working. If i try to run my Avast, Zonealarm, Spybot, i will get a message saying "not a valid win32 application". Help please.

Sir Cam Virus, most likely. See here:

http://support.microsoft.com/defaul...

I have the same problem , I cant run avg, avast, spybot , hijack this (not a valid win32 application). I cant even boot from safe mode.

I have been able to run a trial version of bullguard but my problem still persist

I used other machine to scan for it and found trojan W32.Beagle-AAW, and worm W32.Beage-YN. Removed them but still not working.

If this PC has used Norton and you did NOT remove it completely using the uninstaller from their website, nothing will work on the PC:
http://service1.symantec.com/SUPPOR...
Same goes for McAfee, use their uninstaller.

If that still doesn't work, use regcleaner:
http://www.majorgeeks.com/download4...
and remove ALL instances of Norton and McAfee

Some HELP in posting on Cnet plus free progs and instructions Glad to Help!

I found some help here...This one is a bad one. I am working on it. Deleted srosa.sys, hldrrr.exe (prefetched) I will update.

http://www.symantec.com/security_re...

I hooked the hd into another computer and boot to safemode, deleted all the files mentioned above and the folder of zone alarm (in both my program files and system32), avast or whatever virus program folder, and spybot folder. Now it is working fine for now. I have been able to reinstalled the avast and zonealarm again.

Update: Install spybot sd, update and check system again. It seems clean whatever left.