Geforce 6200 Graphics Card

Hey, previously my computer has been rebooting itself when i am playing games and watching films. I took out the hardware and cleaned them all then when i came to start my pc again it boots up fine , but when it is meant to come up to the login screen, it displays,"no signal or cable unplugged or no power", but when i take out my 6200 card and put the monitor connector onto the motherboard everything works great, but i cant play my games and program without a graphics card too muh fun i play world of warcraft good game, any solutions on how to fix this problem please i am in all ears.