Problem with LCD that should have 1280x1024

[Guido Hochuli]

 LC_ALL=C) an <address@hidden,

Dear Sir
I've got a Targa-PC with a Nvidia Gforce 6600GT graphiccard 64 Bit,
connected to a Targa 19"-LCD-Monitor on DVI. Both from the "lidl"-Store
in Germany.
All running now on Ubuntu 6.06
I can only set 1024x768 and not the desired 1280x1024.
I had the same problem with the latest Kanotix.There the maschine
grumbled, that the installation is not secure, because of the
dualheadcard. But in spite of this, I could make it running on
1280x1024. Under Ubuntu this was not possible.
What shall I do? Is there a possibility to fix it?
Thank you very much for your help and information.
Yours very truly
Guido Hochuli
address@hidden
Switzerland