I had been hit by the virus/worm sircam and it had infected SirC32.exe. Norton Virus Killer could not repair the file and so I deleted it. BUT - now I can no longer open any applications - this error message is given:
Windows cannot find SirC32.exe
This program is needed for opening files of the type
'Application'
Windows cannot find SirC32.exe
This program is needed for opening files of the type
'Application'