For those interested, until last night, I was unable to install CentOS 4.4 onto my PC [MSI 645 Ultra motherboard (P4/1.8GHz,1.25GB DDR, 2x80GB HD's)]

I downloaded the CentOS-4.4-i386-binDVD.iso, burned a copy, and then tried an install. It got so far and the system crashed/hung. I had bad media error after 2% of Linux Media Test. I burned a second copy, but the same thing happened, so I downloaded and burned a CD set from the 4 iso's. I got a different error when I tried to install from the cd's, it got to the choices screen, and when I hit enter, the boot sequence started ok, but it halted with a Kernel Panic, as follows:

Kernal Panic - not syncing:
Include/smp_lock.h:25:Spin_Unlock(Kernal/sched.c:c03681a8)not locked

<0>Kernel Panic - not syncing:
Kernel/sched.c:47:Spin_lock(kernel/sched.c:c04065a0) Already locked by kernel/chewd.c/2605

My fix was to reset MSI motherboard Bios to Factory default and set boot seguence only. On rebooting, the DVD and CD's worked fine. The problems arose from a previous installation, and the way RAM bus speed was synced with the processor bus.