I have just got my computer back from the computer shop which put Windows XP down again. I now don't have a start button, start menu or task bar. How do I restore these?

I cannot put Windows back down myself because Windows jams up when it comes to installing the Sata Drive. (Seagate Barracuda V on an Asus P4S8X Motherboard)

I am a newbie with XP and so far my experiences with it have been frustrating and unpleasant