boot from external usb hard drive ?

Good day all,

I have a littel issue that I'm hoping someone can resove 4 me.

I have a Dell Latitude D610 laptop with WinXP Pro installed with SP2, and it has USB2. I removed the harddrive and put in another one, formated and installed XP Pro in FAT32 on it with SP2, then installed all the drivers. I pulled out the new harddrive and put it into a external USB2 harddrive enclosure. I put back my original harddrive into my laptop, set my BIOS sequence to boot from USB first and let it run.

My problem is, once the black XP screen with little blue progress bar starts, it will stay on the screen for about 10 seconds max and reboot itself, then give me the boot options, i.e. safe mode, normal, etc ... I select normal, and same thing over and over again. I also trien safe mode, and it does start to lead files, and stops half way throught, then reboots ...

I have also done this with only the USB drive connected to my laqptop with the internal drive pulled out, same problem :-(

Any ideas ?

Thank you very much in advance to all !