Hi Thanks for the reply,
Well I tried Ubuntu 9.01 it was worse in the available resolutions.
Then tried a few other Distro's, Centros, Fedora 9 and 11. no good
Then came back to LinuxMint, remember we have other machines with the same screen running LinuxMint and the resolution on them is fine (1680x1050), I will call this the good machine for clarity. The bad machine was running pcLinusOS fine (1680x1050)
Swapped the Video Cards between the good and bad machine, good machine still fine, bad machine still the same. Reset both screens (Asus MK221) no change.
Carried out suggested mods to xconf, no change.
One thing I have noticed the bad machine only offers up CRT-0 in the Nvidia Server Setting Menu and when I run Detect Displays, it looks but does not find.
I have now swapped screens between machines and the Bad screen stays bad regardless so it is a screen issue.
Now I have to find out why same model screen behave differently