Regarding the Samsung SyncMaster, this seems to be the same problem as in my reported bug #255561. I'll try and see if generating an xorg.conf as above will work. (Using a floppy won't be necessary, I could just mount the partition with my /home directories and copy it there, probably as root after doing
sudo su -
I previously tried editing the xorg.conf based on ones generated by Knoppix and Mandriva live CDs. An issue is whether the generated xorg.conf file(s) will result in H/V sweep rates within the monitor's allowable range; another is whether the new software will attempt to override the xorg.conf settings.