Ubuntu always seems to freeze in the first ~15 minutes of when it's booted on my machine. Sometimes it's in the first 5 minutes, sometimes it takes 30 minutes, occasionally it never happens...
I can't reproduce it deterministically, but it happens often enough anyway that I probably just wait for it to happen again.
How can I diagnose the freeze to figure out the cause?
Note to close-voters:
No, this is not a duplicate of this question. This question is about diagnosis, not a temporary recovery. The answers on that question only tell me how to kill the X Server, use the Magic Combo to reset the kernel, etc.... which doesn't help me figure out the cause.
Ubuntu 11.04: 2.6.38-15-generic #66-Ubuntu SMP x86_64 GNU/Linux
The mouse sometimes moves around, but the UI never responds.
Pressing Ctrl+Alt+F1 to get into a terminal doesn't work.
The Alt+SysRq combos do work... and seem to be the only things that work, aside from the mouse (which sometimes also can move around).
I'm not running out of any resources (many gigabytes of RAM and file system space are free)
Possibly relevant hardware (from the Hardware Lister application):
AR9285 Wireless Network Adapter (PCI-Express)
GT216 [GeForce GT 330M] (I'm using the Nouveau driver, which seems to work well)