I borrowed my computer to a friend and when I got it back it seems to be running slow. Is there a way I can tell, without taking apart the computer, whether he took out my fast processor and swapped it with a slower one?

Right click My Computer and then click Properties.



Or here is a detailed scanner: http://www.cpuid.com/cpuz.php




Otherwise:



As a first response you might want to post a HijackThis log for review by our Pros in that section:

Please follow the instructions HERE & then post your log in a new thread in the Spyware, Adware, Viruses and HijackThis Logs section.
(Not in this section please).

Please specify what issues you appear to be experiencing along with your log.