Slow User Switching

Please help. The exact same PC used to have Windows XP Pro, and FUS was very fast. Now that I've upgraded to Vista, FUS takes about 40 seconds just to get to the account selection page. Then another 10 seconds to switch to the already logged in account.I've looked at the Performance/Reliability logs, but nothing jumps out. How can I figure out what's taking so long? I've tried uninstalling all extraneous services, and disabled most hardware devices, but no luck.My machine is a Pentium 4, dual core, 3.2GHz with 1GB RAM, with a 4.3 Windows Experience Index. I'm running Vista Home Premium, 32bit.Please, please help. Cheers, Dan.