Screen resolution problem - I get black borders

[suffer some]

Hi,

I'm having a problem with the screen resolution on my computer: if I choose any resolution apart from 1680 by 1050 (the size of my screen, I guess), then it just reduces the size of the picture rather than the resolution - I get a small window with a large black border, and can only see or do anything within the small window.

My computer:
Dell Precision M4300
Intel Core Duo2 CPU
NVIDIA Quadro FX 360M graphics card

I'm running Windows XP Professional, with McAfee virus scan software.

I'm not sure how and when the problem started: I only noticed when I tried to run Counter Strike for the first time in a long time and it automatically changed the screen resolution.

[suffer some]

Sorted the problem with help of a friend. This is what I did: Went to NVIDIA control panel (under "advanced" in display settings) and changed "flat panel scaling" from "no scaling" to "NVIDIA scaling".