In all honesty, this problem really is quite strange yet dissapointing in the communication between my 8800gt and my ASUS monitor.
I recently had a poor old LCD that was VGA connection and used an adaptor to my 8800gt. I recently bought myself an ASUS 22inch LCD and cannot seem to be able to change it from VGA to DVI.

The general hardware options on the monitor give the option to go to VGA - DVI, however when selected to perform at DVI, the selection resets and conforms back to VGA.
I started hunting down into my Nvidia settings and could not find any problems relating to this and cannot find any override.
Has anyone had a similar problem before?
The answer is proberbly staring me point blank in the face but for the life of me i have no solution.