Hoary freezes about every 15 or so hours

[l.ed.nicholson at sympatico.ca]

Fellow ubuntu users

Please advise on how to fix this freezing problem.
When I first upgraded from Warty to Hoary, there was no freezing problem.

I had problems burning DVD Iso files so tried using PC Nero under VMWare.  
It didn't work but I think some of the fixes recommended by VMWare may have 
corrupted something in Ubuntu.

I don't know if these changes were only internal to VMWare or if they did 
effect Ubuntu but here they are:
1) Use DMA when Comm with DVD/CD ROM devices, and
2) Reconfig virtual devices as SCSI.  This asked for a driver that caused a 
crash during save.  I never did install it.  When switched to simulate SCSI 
this caused hang on restart.  I ran Repair on VMware tools then on next 
reboot, VMware would not run.

I gave up on VMware, configured as dual boot and Nero works well in XP.  So 
I can now burn DVDs.  I removed VMWare but it still shows under system 
tools.  Synaptic does not see it installed.

But now back in Ubuntu boot, my computer crashes about every 15 or so hours. 
  I have been searching for RTFM but haven't found a solution yet.  I did 
come across something about a possibility it could be related to a "X.org" 
eating up all resources, but I haven't a fix.

Hoary freezes whether programs such as Azureus are running or not.

Please advise on fix or where to find a suitable RTFM.
Thanks in advance for your assistance.

Ed Nicholson