Possible motherboard issue?

Hi all,

I've got dual AMD Opteron 244's on an MSI K8T Master FAR2, with 1 gig of dual channel RAM, 1 SATA HD, 1 optical drive (IDE). POSTs fine, ram test is fine, memcheck86 reports no problems. System boots from Knoppix live CD without apparent problems, but installation of multiple OSs to the HD fails on either install or boot (same results using either a SATA or IDE (ATA/133) HD):

* Windows XP install CD won't proceed past ("Setup is detecting your hardware"); blank screen, no error, no activity
* Fedora Core 6 installs but won't boot
* Vista RC1 (legal copy) gives BSOD/stop error in ntoskernel during post-install

I've replaced the HD, and removed each of the two RAM chips separately. Reseated all components, replaced IDE and SATA cables, and used confirmed good install CDs/DVDs. Nothing has alleviated these problems.

Questions: Does anyone know if this behavior could be caused by a motherboard component failure? CPU damage/failure? I don't have a spare motherboard; any suggestions for diagnostics?

Thanks very much,
- Jason