How to fix screen on my computer?

How can I fix my computer screen?

• I have a 27 in Tv with my computer hooked up to it. Last week I went from the regular AT&T DSL to a AT&T DSL dry loop. Where I use the land line for my computer connection only. Well, while the computer tech was here hooking everything up, my wallpaper page would only fill part of the screen. It took him for ever to fix it. Now it is doing it again. There is about a 6 inch black strip on the right side of my screen and I can't see the start button on the left side of the Screen. When I'm on line, I have to use the minimize button just to see the whole page. Why is this happening and can I fix it myself with out calling in another tech and have to pay again?

• Answer:

  hmm, first thing you can try is making your tv auto calibrate, using your remote>menu>display or something like that. But if this happened when the AT&T dude was around, then he might have messed up the cables behind the TV, make sure the signal cable is hooked up properly(on both ends), and if you're using a VGA connection make sure the little pins are all straight