Incorrect, Mike. The IDE RAID controller on the MSI board is one of the ATA133 ones for which XP does not have built-in support. Regardless, the NT family is very picky about having unrecognized IDE controllers swapped in without getting some sort of driver first. And that means, it has to know what's there before switching the hard drive to it. As it appears he's switching motherboards, your suggestion just won't work. Otherwise, what your saying is true.
You're pretty much gonna have to reinstall. Changing the IDE controller out from any NT OS (NT/2K/XP) is basically asking for a reinstall.
There is safe mode in XP, but if you've switched IDE controllers, it'll do you little good. Do a reinstall. If you need to get into safe mode, hit F8 before the white progress bar starts going, or even better, before you see it.
There are most definitely some unfamiliar things about XP, as it's based on an entirely different core than 98. It's NT vs. 9x.
Oh, for that MSI board, make sure you all the files of the driver on a floppy disk so you can install the Ultra ATA/RAID controller during installation. Right when you see the blue screen at the beginning of the install, hit F6 'to install SCSI controllers'(And yes, Windows will think you have SCSI). A few minutes later, you'll have to feed Windows install that floppy with the ATA/RAID controller.