Okay.
It <i>shouldn't</i> damage the monitor for you to run it at 2048x1536@60Hz. Which is the entire point of it being listed in the monitor's specifications as the highest resolution and refresh rate that the monitor is capable of producing.
But ...
Older monitors, like all hardware, do not always respond well to being subject to undue amounts of strain, for example, like older hard drives and burn-in programs that stress the devices to their fullest capabilities. It's exactly this kind of thing that might push a device "over the edge", and cause it to weaken, or fail.
In other words, if it was brand new, I might chance it. Once. If I just couldn't help myself. But if the hardware has got some age on it, I'd leave well enough alone, and be satisfied that you have found the answer as to why the higher resolutions and refresh rates are not immediately available as a user defined preset in Windows.
I have seen what happens when a monitor is pushed past it's specifications, although not with an AG monitor. (Most of these being too expensive to play with.) With an Invar Shadow Mask-type monitor the screen appears to "melt" in places. It only takes a few seconds, and there is no going back once it occurs. It can be nearly impossible to see the screen in order to access the onscreen controls, and although you can boot up in Safe Mode, you can't always alter the resolution/refresh rate for when Windows boots normally.
And so, while you may wish to satisfy your curiosity, I'd resist the urge, set the monitor at the recommended preset level, and find something else to break.
Just because you can, doesn't mean you should. You can get naked in public, too ... but you might get arrested when the old ladies faint.
My monitor originally cost about a grand, but prices have dropped since then. The newest model from the company, which is the 512, can be purchased for around $700.00, which is a great price, IMHO. Check it <A HREF="http://www.cdw.com/shop/products/default.asp?edc=317902" target="_new">out</A>. It is an incredible monitor for being under a thousand dollars.
By the way, you can see why it might be a good idea to be as specific as possible and take the time to list the kind of hardware you are using when you are asking a question. No one can see your computer online, and having a way to verify the specifications for a device can help immensely when troublehooting. This is one of the reasons that I have my hardware specifications as a part of my sig. It can save a lot of time, in the long run.
See ya!
Toejam31
<font color=red>First Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=17935" target="_new"><font color=green>Toejam31's Devastating Dalek Destroyer</font color=green></A>
<font color=red>Second Rig:</font color=red> <A HREF="http://www.anandtech.com/mysystemrig.html?rigid=15942" target="_new"><font color=green>Toey's Dynamite DDR Duron</font color=green></A>
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<font color=purple>"Some push the envelope. Some just lick it. And some can't find the flap."</font color=purple>