I had a similar problem one year ago (at least) when using RabidVWM (in some conditions only, as I can remember) and it only happens (on my Win2K box) when MS-Office was instaled. There's an exe running in background (sorry, I don't remember the name) which is installed each an MS-Office app is run. If you prevent this exe to run at startup (using BlackICE, for example) you will solve the problem.