I recently tried put my HD into my second computer because it has a faster processor.  When I start it,it goes to a message about which mode I'd like to start in, but none of them work, it just starts over.  The HD has WINXP on it.  It was in a MOTHERBOARD with and Intel celeron 433 and I want to put it into the Intel Pentium III.  When I tried to put it back into the original, it does nothing.  What do I do?

In advance, Thanks for any help.First off, it's never a SURE thing to be able to move a windows installation to a different MB.  If you connect it to the original installation and BOOT it up, you can prepare it and give yourself a better chance of it working.

Uninstall any motherboard drivers, and any hardware device drivers that won't be on the new machine.

VERY IMPORTANT:  In device manager, uninstall EVERYTHING under IDE ATA/ATAPI Controllers.

Shutdown and put the disk into the new machine and attempt to boot.

Also, if one machine has an ACPI compliant BIOS and the other one doesn't, that's frequently a sticky issue.  You might disable ACPI in the new machine to see if that helps.