If it has always been slow, you should contract the seller to let them know that you have an issue.
I have a 3.2GHz P4, 2GB RAM, and a 128MB video card, but when I run a game, I need to turn its video settings almost all the way down, or else the game chugs. I don't think that adware or spyware is the problem, because my computer has run slow since the day I got it. Can someone please help me? I don't expect the computer to run flawlessly on a game like Doom 3, but I can't even turn The Sims up to its highest resolution anymore without problems.