I was with a friend of mine where I installed Slack.
A little while ago the system was borked because the monitor was screwing things up (dualboot Windows - Slack) and I had to reinstall Slackware.
So he bougt a new monitor and tonight I was over there to set xorg.conf up again.
Everything was fine and I was installing some new software (frostwire, from SlackBuilds.org) when all of a sudden I get errors (some of them glic related). Thunderbird wouldn't start, installpkg didn't work, pkgtool, even shutting down the machine wouldn't work. After rebooting Slack didn't start at all.
Windows still boots, but I'm afraid that is only a matter of time...

I haven't got a clue what is wrong. Could it be that JFS gets corrupted?
Is there a chance I can get things back in order again?

First of all, if your monitor dies there is no need to reinstall the system on the disk -- just connect a new one.

You haven't provided enough details about what you've done, but if you remove or try to modify the glibc package it will bork the system. It's still recoverable though, there was a recent thread about reinstalling glibc without a complete system reinstall.

Also, don't forget to check the md5sum of your installation CD/DVD to ensure that you don't have a corrupt disk.

You are right, I should have given some more details.
My friend is a complete noob, the old monitor went black every now and then (while the system was running) and he would simply press the power button, so yes, that can lead to data loss.
There is no other way I can explain it.
I tried to repair that with Slax, but there were so many -important- files (/etc/inittab, for example) that were just missing, I decided to reinstall.

This evening things went wrong right in front of my eyes. Installing software didn't work, and all the other stuff I mentioned earlier.
I tried to install glibc (no, I didn't remove the old one), but that wouldn't work either (installpkg/pkgtool didn't work), with the result that Slack won't even boot. No kernel panic, but (as I remember correctly) al kinds of files that couldn't be found.

I'll try to find that topic about reinstalling glibc, but to be honest, I'm not very optimistic about it...

You just boot from slackware CD/DVD, mount your / partition in /mnt
find the glibc package in slackware CD and reinstall it with

ROOT=/mnt upgradepkg --reinstall glibc-(version number).tgz

Thanks, I'll try that tomorrow.
Strange though, that it suddenly just goes wrong.
How is that possible?

I don't know, maybe damaged filesystem caused by instant power off
in this case, beter re-format the partition and reinstall, it would be the fastest way,
and maybe choose another filesystem. I use reiserfs on mine and it did support many instant power off, and power failure (I use it for 4 year now)

Now I don't see what you were trying to do. Why try to reinstall glibc when some software install didn't work? And what exactly is the error in that software installation? You should never ever have to touch glibc, so you can forget about reinstalling it. Please make sure that your CD or DVD is not corrupt, then reinstall, and (if you run into problems again) give a precise description of the events and debug info (e.g. error messages you get). Good luck...

The first thing that went wrong was Thunderbird not starting. So I tried that via command line. The error hinted (Firefox was still open, so I could use that) to glibc. Other errors from other programs also pointed in that direction. It happened right in front of me, didn't mess around with anyting, except that I installed FrostWire (with a SlackBuild script, after installation that worked OK, we even downloaded some music).

I know you shouldn't mess with glibc, but at that moment, (barely anything worked anymore) it seemed like a good idea to reinstall glibc.
Which failed, by the way, installpkg didn't work anymore.

Sleeping a night over it, I think it's just best to reinstall everything.
Question remains: how is this possible?

If re-installing doesn't help make sure to check your RAM and HDD for failure. memtest86 and SMART diagnostics test, if you don't have these programs on some disk try: http://www.ultimatebootcd.com/

adriv, so the problem appeared only after you reinstalled glibc, right ?
If yes, just reinstall glibc with the Slackware install CD/DVD, should be a less than 5min operation

I think he reinstalled it after getting glibc-related errors (it's glibc and not glib, right?)

adriv, if you get glibc errors then either your installation media is corrupt (remember the md5 checksum) or you may have a hardware problem as TeXMeX suggested. But you should first do the md5sum and see.

Thanks everyone for the input!
I've made up my 'plan de campagne'.
First I'm gonna get that pc over here and run some tests like memtest86 and fsck.
If that doesn't give me any leads I'll reinstall Slackware, this time not on JFS but on Reiser (or Ext3, dunno yet).
The CD's I've used were used on 4 other machines, without any problems, but to be absolutely sure, I'll download the ISO's again and burn them on new CD's (and check the md5sums).

The problems did not arise after I reinstalled glibc (which failed anyway, because pkgtool didn't function), but before that.
With Google I found out that the errors were related to glibc.
Otherwise I wouldn't have touched glibc.

Just check the existing ones first, if they're OK, no need to re-download.

I don't have these ISO's anymore.

Hi,

I would check all the md5sum(s).

If you downloaded the cd/dvd iso then be sure to check the md5sum for the original iso. From the cli;

If the iso md5 is ok then you should try 'CdromMd5sumsAfterBurning''.

This way you will know if the burn was OK!

This will check the download iso with the known md5sum that you also get with the iso.

Slow the burn if you have too!