My computer will start booting up but no load

Hello,

when computer starts it loads up the window icon with the 4 squares and then stops will sit not moving for at least 20 minutes or more. When I manually turn it off and back on, it will
come up with the: "Repair Windows or start windows normally. I click start windows normally and sometime it will take off and sometimes not. For awhile it was every other boot, now more. Also, when I am away from my computer for 20 minutes or so, I will get a blue screen on my monitor with "no signal" and orange light on my monitor . It is not in hibernation or sleep mode.