OK, I have a dell xps-710, 2core 6400, 2gb ram, 2x 500 gb harddrive. I upgraded to vista, now I am have this problem, everytime I restart and sometime when I start-up, windows vista locks on the sign-on screen. Ihave to shut-down manually one or more times to get it working, when I upgraded vista I made sure my bios was up dated and everything else, I sent this message on the forum, but wrong catagory, (hardware) and was told to go to software, and  told me to download (redgister cleaner) which I did but Same thing kept happening only this time it got harder to long on, so I uninstalled register cleaner and I was able to start-up ,but I still have the problem, does anyone have any suggestion as to how to remadie this situation.