These steps are only for really bad hard disk muck-ups and accidentally deleted files. For normal filesystem inconsistencies, don't use these steps!
Run the command: reiserfsck --rebuild-tree -S -l /root/recovery.log /dev/hda3
You need to be root to do this. Read the reiserfsck man page for what these options do and for more options. Some interesting options are '--rebuild-sb, --check'
After the command finishes, which might be a long time for a big partition, you can take a look at the logfile /root/recovery.log if you wish.
Here's a useful link for more advanced tricks.
I just want to thank for the tips on recovering deleted files. I've just wrongly deleted some files and been able to recover them by following your steps / steps from pages mentioned herein. Instead of finding deleted files in lost+found directory, I've ended up finding them in the original directories (from where they were deleted). I've compiled the sequence of steps for my specific case (slight changes will suit particular issues regarding unwanted file deletion), which follows:
Recover deleted files (from /home = /dev/hda7)
0. Unmount partition from where to recover deleted files
umount /home
1. Create partition copy
dd if=/dev/hda7 conv=noerror > /hda7.img
2. Set up device containing copy of partition (created in 1.)
losetup /dev/loop/0 /hda7.img
3. Rebuild FS tree, performing a thorough partition scan and logging to /recovery.log file
reiserfsck --rebuild-tree -S -l /recovery.log /dev/loop/0
(4. Check written log file)
(less /recovery.log)
5. Create directory for mounting recovered partition
mkdir /recovery
6. Mount recovered partition in directory created in 5.
mount /dev/loop/0 /recovery
7. Access recovered partition's lost+found directory and look for files
cd /recovery/lost+found
8. If not there (7.), then look for in original directory
cd /recovery/
9. Remount /home partition
mount /home
10. Copy recovered files from 7./8. to /home/
cp /recovery// /home//11. Unmount recovered partition
umount /recovery12. Detach recovered partition device
losetup -d /dev/loop/0
@nT$