I've had a weird problem on an Intel MB with stapled on 82865G graphics video. Over the time of 2010.07, I've had it crash to the login gui.
At first, since it was set to auto login it would go into a loop. open to kde, crash, relog itself in, rinse repeat.
I think I changed some video parameters to fix it, but don't remember details.
It is using the Intel 810 and later module.
Now after running a long time, weeks maybe, but recently getting the white bull, it is up to its tricks again.
This time I can MAKE it crash to login gui, the one that has root and user names, not the black screen of death.
How? By typing in my router IP address. 192.168.1.1
What the heck? anyway, what logs can I look at to see what happens?
Using latest FF in synaptic, and unit is all legal synaptic and updated.