Vista - monitor not working; can't change settings

I could really use some help please

I am running vista business version of windows and I just purchased my pc a few months ago 64bit. Anyway, I normally run my pc with a 24 inch monitor and have now plugged in one that is more square in display ratio.

I was in personalization and unchecked something ratio because the monitor was showing everything warped and stretch and now my monitor only displays "input signal out of range" so I cannot see to change it back.

Does anyone know how to change display settings without a displaying monitor?

Monitor works fine in safe mode but not in normal mode

if you have a monitor plugged in that displays correctly, then all you have to do is set your resolution to 1024x768 and set the refresh rate to 60hz (by using the old monitor), you could also try a system restore to get any settings that you have messed up.

Boot into safe mode and change the resolution that way.