Screens go blank briefly and return in a different resolution setting.

My screens are randomly going blank for a brief moment and then returning to a different resolution setting. Then about 5-20 seconds later the screens flick blank again and return to the correct resolution settings.

I have done a fresh install of Windows 8.1 and I am running dual monitor. The video card is a GT420, my CPU is an i7 and i have 8GB of RAM. The PC is a Dell Vostro 460.

It was doing it then it stopped. I was able to work all day without this happening yesterday. But today it is happening quite frequently and it is very annoying.

I have

• Upgraded to the latest Geforce drivers.
• Upgraded my systems BIOS.
• Upgraded all Windows updates.

This seems to happen when

• the UAC (user access control) prompt appears,
• When using office 2013 (i have disabled hardware accelleration).
• Opening the GeForce experience application
• And it just happened randomly as i write this post!!

Can somebody help me please?!?!