Hi
Three suggestions after trying all the above, based on problems I had:
1. Power Supply can't cope. Not all 300W are the same, I bought an Enermax which puts out 185W on the 5v/3.3v, my old one put out 150w.
Didn't make a damn bit of difference though, but I've got meself a nice PSU now.
2. Check all HDD connectors. I use a pair of long nose pliers to tighten them all. As you make/break connections they loosen, and one of my RAID drives was cutting out. Not nice.
3. My CPU is unlocked and overclocked to within a few MHz of it's life. It's a Duron 800 at 7.5 X 133. At anything but "Default" in the CPU multiplier in the BIOS, it hung randomly even when 8x was selected. The L1 bridge trick drops a few millivolts, so I had to increase the core voltage. If you can, put it up the barest minimum and see what happens.
GBN
Epox 8KTA3+, Duron 800 at 7.5x133
768 MB Crucial CAS 2 PC133
2x10GB Maxtor 7200rpm ATA 100s as RAID 0
15Gb Maxtor 7200 rpm ATA 66 as backup drive
16/10/40 CDRW
GF2 MX400
+usual bits
I can now CD copy on the fly whilst simultaneously defragging all drives and doing a full virus scan. And surf while all this is going on. That's multitasking.