This Acer monitor will just not work with the 'out of the box' Ubuntu 10.04. After many hours of hunting (I am not a Linux fundi), I finally found the solution by combining many suggestions from different threads. To try and save somebody else some trouble here is the solution:
a. A Windows PC to extract the monitor hardware info (EDID).
b. You need to download moninfo.exe from _www.entechtaiwan.com - shareware. If you need to adjust the position of your video you can use xvidtune that comes with Ubuntu, but be careful when you use it. It will also provide the info that you need to edit xorg.conf, but I only ran it after fixing the problem, so I don't know whether it got the info from the monitor or from xorg.conf.
c. You must have installed the latest NVidia display driver ( System/hardware/drivers). Install through the above sequence to ensure the driver is the latest that matches Ubunti 10.04. Fixing a drivers version mismatch can cost hours (ask me).
1. Plug the X223W into the Windows PC and run moninfo.exe. It will display a huge amount of info about the monitor. Copy and paste this into a file and save it - you will need it to set up your xorg.conf on Ubuntu.
2. Plug the monitor back on the Zotac.
3. sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf-save
4. vi /etc/X11/xorg.conf
5. A few entries need changing - they are highlighted in the attached xorg.conf.txt. Do not copy this file over your existing xorg.conf, rather edit and make the changes yourself, in case there is a hardware difference with your monitor or Zotac. The entries are each marked.
6. Look in /var/log/Xorg.0.log for errors (note the capital X in Xorg.log) after rebooting if it did not work.
Good luck it took me a while to get it to work. The three changes are all critical.
xorg.conf.txt 1.888671875k . file