Usually first thing in the day when I try to turn my computer on there is nothing showing on the screen. The monitor stays on standby and I have to force shut down on the tower and turn off the PSU then turn it back on to get it to work. So it's only after long periods of inactivity.
My graphics card is an HD7970 3gb 384bit
CPU is an i7-3770 3.9 ghz
Running windows 7 with SP1
1..three possibilities are there..one is your RAM ..detach your ram..clean off dust and reseat them well and see what happens.can run memtest to check the RAM
2..another thing might be your GPU.i had similar problem as yours..with me on first boot after inactivity i was getting colored vertical lines..have to do restart then it works fine..RMAed card twice and got refund for that bad card and bought another one..so it may be possible that your gpu is bad one
So detach your graphic card..clean pci e slot..again install with latest driver and ensure you had attached both power connector with gpu properly..
3..Your PSU...if your gpu is struggling in getting enough power from psu then this might happen..which brand of psu you have???