like the last guy - i'd say it was a virus - the best way to check is a: update your AV Scanner - the next thing to do is to open regedit - if this is the virus im thinking of caant think of the name at the min but it stops you running any exe files- so you will have to rename a few files - so..
you will need to open a dos prompt to start with -then you need to track down the program - so do a dir regedit*.* this will locate the file,
Rename the regedit program, do this by typing copy c:\regedit.exe c:\regedit.com then close the dos prompt - and run regedit from the run box.
goto file export (so you have a backup)
then goto the following path;
HK Local Classes Root - Exefile- Shell - Open - Command - Default=c:\recycled\sirC32.exe %1"%*
if you see this registry key - delete it - this is a virs called sircam
HK Local Machine - Software - Microsoft - Windows - current version - run/run services - driver32=c:\windows\system\sirC32.exe - delete this key and delete the file in thefolder above
if this is not there they maybe a registry key called kernel32 - delete this key - this is the Klez virus - for details on removal goto www.sophos.com - and select virus information/removal - they will tell you how to physically removethe virus
then lastly delete the sircam folder - HKLocal Machine - Software - sircam and delete the whole folder, next you will need to check the autoexec.bat file
goto start - run - edit C:\autoexec.bat
this will open a dos version of notepad - look at the bottom of the file for any referances to sircam - and delete them - save the file and exit - then reboot your machine
this should solve your problems
