I ORDERED an off-lease machine thinking it would be no big deal to install an operating system. Machine is an IBM ThinkCentre S51, 8171-21U. Getting command prompt when I turn the machine on under Windows 98 wording. I can't seem to get it to boot from my XP cd. Also can't get the light to come on on the cd drive by typing in drive letters. It will READ the floppy drive by typing in letters. I need to get to the BIOS to change the boot order if possible. Or any other suggestions to get this thing to read my XP disc? I've DONE a clean xp install but never ONE over old Windows installation.

Thanks! If you are doing a clean install then you are not installing "over" anything. You are correct that you need to change the boot order in bios so the cd is the first device. Then boot to the XP CD, format the drive, and do the clean install. If you don't know how to get into the bios watch the screen when the system first boots for a message saying "press for bios (or setup)"

or go here:

http://www-307.ibm.com/pc/support/site.wss/YAST-3JWKJX.html
or here
http://pcsupport.about.com/od/fixtheproblem/a/biosaccess_pc.htm OK, I thought I'd tried F1 to get into the BIOS but apparently I hadn't because it TOOK me right in. Just as a side note, I was able to use F12 during power-on to choose an alternate disc to boot from just one time. Thanks!!You're welcome. If you run into any problems during the installation just post back in this thread.