Error message regarding refresh rate from the start

Greetings,

I have a problem with my old crt monitor. It's a Mitsubishi Diamond Pro 2070SB.

Now from the second I activate my PC it shows me a small monitor message reading "Refresh Rate Lower Than Recommended Refer to User's Manual for more Information". This messages only disappears after Vista sucessfully loaded, but now I have small errors regarding the correct size of windowed programms (they are slightly out of sight on the upper side of the display).

I already tested a brand new graphics card (9800gtx), and it's still the same. Well, seems it's something wrong my the monitor itself. But what exactly and do you guys have some advice how to fix it?
The monitor itself is now close to five years old.
It would be a shame if I'd have to trash this wonderful piece of monitor.

I have updated to the newest nvidia drivers. My OS is Vista64.

Thanks in advance for any help you can offer,