Restarted my computer and now I get no signal on my monitor?

if your motherboard has onboard video see if the motherboard using the onboard video port now. (gpu failure or bios glitch). if the onboard video is working look in the bios make sure primany display set to peg/pci. sometimes if it set to auto the mb can fall over to onboard. if there no onboard video turn the pc off. try clearing the cmos to see if it a bios glitch if the video comes back check to see if your mb running the newest bios. if there no video. try another video card then a test power supply.