Hi!
An error message like this can mean a lot of different things, unfortunately. Should you get the message again, please write it down verbatim, as that would help a lot in diagnosing your problem.
A good starting point would be to make sure that all your BIOS settings are correct, especially those that relate to your hard drive (things like RAID/No RAID, auto-detect, IDE/SATA, on-board device settings, etc.). If you do not know what a setting should be, I'd refer to a website like
www.tomshardware.com or
www.overclockers.com for reference.
The next thing to do would be to get a known good stick of memory from another machine that is working fine, or if you can't do that, buy a small stick of new memory to act as a test device (there is also software that you can find on the Internet (like memtest) that will check out your memory for you, but those tests are not foolproof). Try installing XP with just that one stick of memory and see if you can complete the installation. If so, then your at least some of your original memory is bad.
Assuming that it is not likely that 2 hard drives and 2 copies of XP are bad, if the culprit is not the memory then there are only 3 things left that are likely to be the problem: 1) Your power supply (I keep a good power supply on hand as a spare for these situations, since you can get a 450-500 watt unit for $30 on sale) 2) Your processor (not likely, given your description) or 3) A defective motherboard. If you do all the things I've described and still have the problem, I would advise you to document all your troubleshooting steps thoroughly and then contact MSI. My experience is that they will RMA the MB if it is still under warranty.
Good luck. Please let me know if this helps. A rating would be appreciated if you deem it appropriate.
Bob