cpu monitor is blank

i recently bought a new desktop and a new monitor. i connected the monitor to my desktop and it was working fine at first until i installed the driver for the monitor. The picture quality became horrible and kept on lagging when i was watching a video. So, i was trying to somehow fix the resolution or the rtm and disabled the graphic adapter in the display settings. When i tried restarting the cpu, the monitor became blank and doesnt work anymore. Does anyone know how i can fix this problem?