my moniter was working fine for a week after i brought it but now when i turn it on there are vertical black stripes going down my screen, also the end of the screen at the right is over on the left hand side. It is nothing to do with the signil from the computer because i have tried it on multible computers with multiple cords. The moniter is a 19" AOC widescreen LCD and i am using windows vista. does anyone know what is wrong with it?? Thankyou