I have tried two different Windows 7 Professional DVDs and neither one worked.
I haven't tried booting any other DVDs, but I will tomorrow evening. I can try Windows 2003 Server and/or Linux to see if it recognizes it.
I suppose it could be a problem with the DVD drive, even though it only has a total of about 15 minutes of use on it.
I know it's not really the ideal machine for using as a desktop, but the dual quad cores, 8 GBs of RAM and RAID 10 seem like they might make a nice video editing workhorse. I've already added an updated video card in it. I hate to not to be able to use it (for what I paid for it).
I'll try a couple of other discs and perhaps another DVD drive if need be, and will check back.