How to distinguish non-ms origin services

Imagine you are employed by a company which has a dual – CPU system which runs on Windows XP Professional and you are to manage this system. Now imagine there are quite a number of programs which are running simultaneously and you are bothered by the effects on performance which is brought about by third party software services.
Now the big question is how will you distinguish between those Non-MS origin services from the rest of the programs, for aims of trouble shooting?
Your ideas might really help.
