Running Windows 7 Home Premium with 2 monitors (1 new Acer + 8 yr old Dell 1st gen "flat screen") & AMD Radeon HD 6450 graphics card. Worked fine for 2 months. Now Dell says "Cannot Display This Video Mode". Can't figure out what happened. Help!
Did you update your video drivers recently? Go into your display properties and look at the resolution settings for the old monitor. It may not be able to support anything higher then 1024x768(check your manual).