anyone ever experience the problem of using xlockmore or xscreensaver, locking your session, coming back later and nothing works? black screen, can't login, do anything, you just have to reboot?

I have had this happen on quite a few occasions, with this last time being the worst. I couldnt do anything with the keyboard to even get to a console, reboot, and even the numlock key wouldnt turn numlock on/off.

i didnt have my freebsd machine up, so i never did try ssh'ing into the box to see what is up. this machine is currently slackware 10, but the same thing happened in 9.1 randomly. its very annoying and requires a hard reboot to fix it.

anyone know what could be up?

I have the same problem. With other, more pressing, things to do, I've just ignored it so far.
Glad to see it isn't just my system, a Compaq EN -- PIII 933MHz, 512MB RAM, CD/RW on hdc,
60GB on hda, 8GB on hdb, 780MB on hdd, no SCSI other than ide-scsi emulation for the CD/RW,
SB 16 soundcard, US Robotics external modem, Lexmark Z53 printer, Canon N67OU scanner,
Matrox G450 video, Kensington ExpertMouse trackball. I've gotten into the habit of jiggling my
trackball whenever I walk by.

Running ide kernel 2.4.26 under Slackware 9.1. Suspect some sort of mis-aligned pointer in
xscreensaver while in kernel space, clobbering the input buffers or traversing an infinite loop.
May even be a piece of data being read as a HLT instruction bringing down the CPU. Not having
the intelligence of Linus, I doubt I'll ever be any help in tracking down the cause.

I'm glad to see i'm not the only one. I have a feeling that this must happen to a lot of people. It's usually when I leave it locked for an extended period of time, such as 8 hours. very annoying