Install and scan with
Spybot Search & Destroy in case you suspect there being some directly detrimental programs running. Other than that, uninstall programs that you aren't using. Google is also a pretty useful source for information about unknown executables.
By the looks of it at least there's nothing unknown that seems to be hogging much memory or CPU time.
Autoruns is a program that's useful for finding out what programs are automatically starting with the system, with the option of toggling such programs on and off. Though it might look confusing at first as it lists so much information, the key is to look at what's listed under the Logon tab.