Office 2003 Locking up

Hi,
When Excel or Word loads it gets to the blank document or spreadsheet and then freezes. I can’t kill the word.exe or excel.exe process, even in task manager. I have to re-boot. After un-installing, deleting directories, running a registry cleaner and then re-installing clean, the problem still occurs. System restore keeps failing. I finally found that running msconfig and stopping all services from loading fixes the problem, so obviously a conflict with a service. But which one. Does anyone know of any known problems with these symptoms for Office 2003 ? Any help would be appreciated in tracking down the problem service without having to go through one by one.
Michael.