If the current monitor is bad, swapping in a different, good monitor might fix the issue. If that works, then you simply replace the old monitor. Of course, exchanging old cabling with other cabling or swapping from DVI to VGA jacks is another option worth testing but unfortunately, you've not told us which type of monitor, jacks, or cabling you're using....
Hope this helps.
Dell Windows Vista Home Basic 08. Cannot get the monitor off power saving mode. I can hear a beeping noise coming frim the tower. Disconnected power cords and reconnected. Moving the mouse and pressing any keys on keyboard doesnt help.