Dimension 2350 fast fan, 100% processor

I have two Dell Dimension 2350 desktops with the same symptoms. I've completely rebuilt them with a fresh install of XP Professional. When I turn them on, the CPU fan that pulls air through the green duct out the back of the case. starts ramping up and is very noisy. So I did Ctr Alt Del and looked at the processor. It's pegged at 100%! OUCH I updated the bios, installed the chipset, made a Floppy set and ran the diagnostics and ever put new thermal paste. Someone even said they found an upgrade for the NIC card and that was the issue. I reinstalled that driver and ran a diagnostics which said everything was okay

After countless hours of scratching my head, I found a program called ProcessExporer which shows me "what" was using all of my processor.! Drum roll please.......Generic Host process for Win32 Services. When I disable it. the processor drops back down to normal but them certain things dont work in windows...DUH

So, the million dollar question is why is this using so much of my processor and how to I correct this problem

Thanks!!!!!!!!!!!!!!!!!