I've seen more posts about frozen systems in the past 2 weeks, and I could use any help/ideas you have. I have two FC5 Dell desktop optiplex GX270 systems and both, possibly co-incidentally, started locking up and crashing about 2 weeks ago. These have a lot in common, but they were not purchased at the same time and so they don't have the same MOBO. Both have software raid, usb keyboards and mice, nvidia 5200FX cards. One system is completely baffling to me. It has been running stable 24/7 for 2 years. Now it completely freezes up while trying to use the mouse. The freeze up does not clear the video display, however. The screen remains a snapshot of its state at the time of death. No responsiveness to the keyboard, no nothing. I have no clear clues about what is wrong here, but I wonder if the problem might not be kernel/usb related. How to find out? Unfortunately, the goddam installonlyn yum module is in place and so I can't boot to kernel 2.6.16 anymore, so I've got to find that (and the video modules for it) somewhere and see what happens. I suspected the proprietary Nvidia driver, which was recently updated, but when I run with the NV driver from xorg, the problem is the same. I suppose I should run under VESA and see what happens. On the other system, the cause of the crash was always using the mouse to re-size a window (such as re-size an image in gthumb or doc in evince). The crash would destroy the video signal and the monitor would go black and the system was comletely locked. Could not ssh in, no keyboard response. Running the NV rather than nvidia driver did not have an effect. I found messages in /var/log/messages indicating that there were errors on one of the hard disks in the raid, and I replaced that disk and now I'm watching to see if it stays up. I was a little bit surprised that the software raid array did not detect any disk errors, and yet there were reports about SeekErrors in /var/log/messages. Just to be clear, the errors were like so: kernel: hda: drive_cmd: status=0x51 { DriveReady SeekComplete Error } kernel: hda: drive_cmd: error=0x04 { DriveStatusError } But the RAID still said it was OK, both drives functional. Some people have suggested I update the Dell BIOS and I've done that. The lock up hits the system suddenly and it does not leave info in /var/log/messages. pj -- Paul E. Johnson Professor, Political Science 1541 Lilac Lane, Room 504 University of Kansas