Ubuntu 11.04 with Unity freezing on new Lenovo Thinkpad 420

No key combination is working for me to recover:
http://en.wikipedia.org/wiki/Magic_SysRq_key

It happens to other people:

http://askubuntu.com/questions/58412/why-is-ubuntu-unity-freezing-up-on-me-sometimes

Many other people:

http://askubuntu.com/questions/tagged/freeze

And no answers for the person who is adding log files and all that :-(

http://askubuntu.com/questions/60965/ubuntu-natty-freezes

Looks like the answer may be no Unity. (This problem description is mine exactly, though i don't notice the lag right before things fail-- then suddenly the whole screen freezes. Things like CTRL+ALT+F1 also do not work at those times.)

http://askubuntu.com/questions/54698/ubuntu-keeps-randomly-freezing

I've over-used it so much the function key now makes an audible click.

This is not my error-- this one can still use the mouse, and ctrl + alt + f1 actually works...
http://askubuntu.com/questions/54089/why-does-11-04-freezes-randomly

Debugging

Asked in #ubuntu:

Lenovo T420, newly installed Ubuntu 11.04 with Unity enabled. Freezes seemingly at random, every couple of days. Firefox is usually at the fore and Skype usually running, if i'm looking for scapegoats. No ctrl-alt-fn-sysreq or any other key combination, including random jamming of keys, breaks me into terminal or anywhere else i can actually do anything. Recommendations?

Here is what i've researched so far: (link to this page)

walking me through / pointing me to docs for getting the log files after a complete system freeze would help a great deal

OK let's just get help in #agaric
09:26 mlncn: do you know what i hit to take a look at that stuff on boot, or is it after it starts
09:27 sfreuden1erg: /proc/sys/kernel/sysrq
09:27 sfreuden1erg: cat /proc/sys/kernel/sysrq