If you can remember the .exe file name it is you could try this,
Start menu - Run, type msconfig.
A window should pop up and you will see a number of tabs across the top, you want to check - Services - and - StartUp. If you find it in here uncheck it's box hit apply and restart. You may find other progs in here you no longer want running too.
I have found this works about half the time, the other half it's a registry key and a pain to get rid of.
Security Task Manager is good at detecting these little shit's and IIRC it highlight's the key entry, or at least gives you something to search for in the reg key. It is a licensed program but the trial version will find problems just not fix them.
An after thought would be, you don't happen to have a system restore point do you? Even if you don't want to use that restore point this might work,
Restore back to an earlier time with (hopefully) not too many changes.
IF the culprit is not there, grab a copy of your reg key, back it up and roll back your restore point to current settings. Paste your back up of the reg key over the current one and your done.
Of course any programs installed between the two restore points may not work now due to no reg key's for them but it may be a case of re-installing those programs that need it. Might save an entire system wipe and install.
Hope some of this helps
Good luck.