Hi o_unit,
First thing you need to do is go into your "Control Panel" and check for hardware conflicts. Don't know how your dual monitor configuration was originally set up.. so can't be more specific without more info.
If you need help with configuration conflicts you can go hereConfig Conflicts
If that doesn't solve your problem.. post back to us for more help.
RGPHNX
PS- you also need to check your "IRQ" settings.

It could be helpful if you would tell us the make, model, size of the monitors.

RGPHNX, if I can undestand what o_unit said, he switched monitors to use one at a time, not both simultaneously.

You are using only one monitor at a time right?

Yes, that is correct, I am only using one monitor at a time. The monitor that works is a View Sonic 27" LCD monitor/tv. The monitor that is not working with my system is a Sharp LCD 15" monitor. The Sharp works fine with my girlfriend's computer but it won't work with my system.

I have checked for hardware conflicts and there are none.

o

Hi again o_unit,
If the monitor is known to be good (ie. works with another computer) AND there's no config. conflicts... then..
about the only thing left is ..
either
>program driver incompatibility OR
>hardware connections OR
>videocard/motherboard incompatibility.
Get & re-install latest drivers from MONITOR manufacturer's website.
Check ALL hardware connections (CABLES, CARDS ..ETC.)
Check monitors manufacturers' website docs for system incompatibility with your system hardware.
Hope this is clear
RGPHNX