programs self uninstalling!?

[nato]

Hi guys.has anyone ever had the wierd occurance of programs dissapearing/uninstalling themselves.
yesterday i booted my comp and low and behold nero,smartdoctor,firefox,thunderbird & avermedia drivers were all missing their desktop icons.when i checked their relevant folders they were either empty or missing all but saved profile files.i tried xp restore but no luck.
could this be caused by overclocking attemps on the cpu,ram or video card?
i'm not sure if this issue has already been addressed previously in another thread. if it has already maybe someone could post a link.
thanks in advance

[bakuryu]

First make sure that u don't have any virus/worm in your system !

Run on-line scans

Online Trojanscanners
http://scan.sygate.com/pretrojanscan.html
http://www.windowsecurity.com/trojanscan/

Online AV
http://www.pandasoftware.com/activescan/
http://www.ravantivirus.com/scan/

Does the un-install occurs every time u shutdown ??
Is your shutdown taking longer ,.... ?
Check out and see u don't have any scripts running at shutdown that is un-installing the programs.
Start->Run->type gpedit.msc
then go to Computer Configuration->Windows Settings->Scripts , double click Shutdown

[-ToasT-]

Yeah, that is neither nor caused by overclocking. Could be virus, could be something else. Firefox on my P3 uninstalls it's profile every few days. Very weird, not that I care.

[nato]

no the uninstall doesn't happen every time to all the programs, so far just one now has uninstalled straight after a reinstall.the program is, Grisoft AVG Free, AV software.the others programs are still ok atm, although i haven't reinstalled the Avermedia software back on yet.
also there are no scripts running at shutdown & the shutdowns don't seem to be taking longer.
I'll try some of your recomended online scans & I'll post back any results.
thanks for your help.

[nato]

ok tried these programs

http://scan.sygate.com/pretrojanscan.html
http://www.pandasoftware.com/activescan/

no problems found.