Do you have antivirus on your machine? This can be virus related. I would install an AV or go to
www.trendmicro.com and run a free scan. Also, what registry key did you delete? There are some that make that run at startup and that is what is causing your error. It is trying to start the program but can't find it. You can also go to msconfig and uncheck it there.
THere is also another windows process with the same name. I can't remember where it is supposed to be located, but I really hope you didn't delete that one on accident. It controls windows sessions.