Every monitor has its own hardware controls independent of Windows. It's usually a button on the bottom or a side you push that will give you the adjustment screen. It'll be a bit cryptic, but you'll be able to figure it out.
After a hard drive crash and repair I connected my 2nd monitor to my laptop. The problem is the desktop does not cover the whole monitor screen. I have a black 1" edge on the top and bottom and a 2" black edge on both the right and left side. I've tried adjusting the screen resolution, but no luck. If I make the 2nd monitor the main monitor it works fine, if make a mirror of the 1st monitor it works fine, but if I just want to extend the desktop to this monitor it does not cover the entire screen. However, I can drag items from my laptop and position them in the black edge area and that works. What am I missing, can anyone help me.
This is a Vista computer with all the upgrades and service packs.