You are.

How long has the 'slowness' been apparent? Have you installed any new programs recently? Mcafee and Norton are notorious for clogging up system resources.

Hit CTRL+SHIFT+ESC at the same time, that will bring up the "Task Manager".

Have a peek through the list(s) and see if anything looks sketchy. I do not advise stopping any of the services unless you are 100% sure that you dont need it to function. Google the process, decide, and see if it helps your system.

OR, maybe a good ole defrag is due.