Comment 34 for bug 109643

I've had those lock-ups in Ubuntu 7.10, just a plain freeze of everything, including network, ssh, caps-lock, mouse, etc.
I use the following hardware:
- AMD Athlon XP 1800+ (1533MHz)
- NVidia GeForce2 MX-400

Installed the binary driver through 'Restricted Driver Manager'

What works for me is editing the file /etc/init.d/powernowd.early and setting:
DO_MODULES=no

After a reboot everything works well. 3D-effects, wobbly windows, everything.

Hope this helps.