It happens really randomly. Suddenly keyboard and mouse stop to react. Screen freezes. However if I have for instance skype running during that "crash", I can still continue to talk over internet. For me looks like x serwer crash. Xorg logs however are empty. I had to hard reboot only to get control over pc (magic sys key + SUB) only works. Trying switch to another session is not working.
I run Slackware 13.1. Kindly asking to help me to solve that irritating issue.
I pasted errors usually I find at Xorg.0.log.old after hard reboot only
22.214.171.124 #2 SMP Tue Sep 14 19:33:55 CEST 2010 i686 Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz GenuineIntel GNU/Linux
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: GeForce 8800 GT/PCI/SSE2
OpenGL version string: 3.2.0 NVIDIA 195.36.15
OpenGL shading language version string: 1.50 NVIDIA via Cg compiler
cat /var/log/Xorg.0.log | egrep "WW|EE"
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(WW) The directory "/usr/share/fonts/local" does not exist.
(WW) The directory "/usr/share/fonts/CID" does not exist.
(II) Loading extension MIT-SCREEN-SAVER
(WW) Genius NetScroll+ Superior: ignoring absolute axes.
Errors from xkbcomp are not fatal to the X server
[mi] EQ overflowing. The server is probably stuck in an infinite loop.
0: /usr/bin/X (xorg_backtrace+0x3b) [0x80a1e6b]
1: /usr/bin/X (mieqEnqueue+0x1ab) [0x809f51b]
2: /usr/bin/X (xf86PostMotionEventP+0xcc) [0x80bc62c]
3: /usr/lib/xorg/modules/input/evdev_drv.so (0xb525d000+0x4781) [0xb5261781]
4: /usr/lib/xorg/modules/input/evdev_drv.so (0xb525d000+0x4a76) [0xb5261a76]
5: /usr/bin/X (0x8048000+0x6d06f) [0x80b506f]
6: /usr/bin/X (0x8048000+0x117774) [0x815f774]
7: (vdso) (__kernel_sigreturn+0x0) [0xffffe400]