[cprgmr]

I would start with the simple things first. One thing that you mentioned that I haven't had any problems with is the BIOS update. I went directly to 1011 without any problems.
Try the following...

- Remove the audio card and go to the onboard sound.
- I made sure the jumper setting xxx was set to allow keyboard wakeup.
- What is the temp of the system when it locks up?
- What are your power settings; is the box going into sleep mode and can't be woken up?
- Go back to 512mb of ram to see if you still have the same problem.
- Do you have a different video card you can try?

Make sure after you do each change that you put the box through all of it's paces again to isolate the offending component. Good luck!

 

[cprgmr]

For PS2, I noticed on my mobo that if I disconnect the mouse, it's frozen after I plug it back in: a minor mobo issue I can live with

FWIW, you might not want to do that. I was under the impression that you can grenade your mobo by unplugging and plugging back in a PS/2 mouse (serial/usb mice are a different story).