Donna, I am surprised but then again not surprised. PC World have been ok for me, but from this Forum I can see lots of unhappy customers with Vista machines not working as they should. Thus PC World has lots of problem computers to sell.
I agree take it back, but then demand to see the manager and give him a choice. He provides you with a computer tested and working in front of your eyes, and you then take it home, or he just gives you your money back and you go elsewhere.
If he is a good manager he will help.