OS: Windows XP
Type of Computer: custom
OS package: SP 2
Ram: 512 Megs

Ok, yesterday I was on tweakxp.com trying some tweaks to speed up my computer and dsl. I think I did a few bad ones. My usb port has not been working for a while so after I tried some tweaks, I restarted my comp and went into the bios to see if I could fix that problem since I was in the mood of computer maintance. I saw that my usb port was turned off, I turned it on and restarted.Now everytime the computer loads, when it gets to my desktop it automatically restarts. It does this forever. I cannot do anything on my desktop because as soon as it gets to there it restarts. There has been cases where it will say the system.exe file terminated and it does a 1 minute countdown nt shutdown. However it never stops restarting itself. I went back in to my bios and changed all my settings to default and cut my usb back off and it still does not work. I will appreciate any help. Thanks...

Can you boot into Safe Mode and use System Restore to a point before you made the changes?

Safe mode won't work either, it freezes during load. My system restore was disabled.