I have Yellow Dog on my 60 gig.
It's the "YLoD", or Yellow Light of Death on the PS3. It does seem to be some hardware failure on the mainboard which causes it. The biggest thing is to keep the system well ventilated. Since the system is out of warranty, it may be worth the extra piece of mind to take it apart, clean out all the dust and put a better heatsink compound in place.
The other failure is the laser diode, which results in the drive not being able to read certain types of disc. If testing take a CD, a DVD, and a BD with you. Though it is possible to find repair parts for the drive if it comes to that.
