I am still fighting to get my Ubuntu Dapper install working correctly on my HP Pavilion zd8000. I am having problems with my machine locking up with a blank screen. I really think it is related to my cpu overheating. I would love a way to prove it. In debugging the problem I added a CPU Frequency Scaling Monitor. It shows my cpu constantly running at full power. Also, it gives me this dang error message every time I reboot.
I’ve recently upgraded to dapper on my laptop and found I have the same high cpu usage problem. If you haven’t already seen this, it may shine some light on your problem:
https://launchpad.net/distros/ubuntu/+source/linux-meta/+bug/30570
I ran into the same problem and found a solution here:
http://ubuntu.wordpress.com/2005/11/04/enabling-cpu-frequency-scaling/
BTW, that blog has TONS of great information in it. I highly recommend it to new Ubuntu users.