About a week ago I ordered a new CPU & power supply for my PC. After installing the Power supply I turned it on to make sure I connected everything. It booted up just fine went into windows then I shut it down. When I put the new CPU in I had a hard time installing the CPU fan, and eventually just gave up on it and put my old one on as a place holder. It booted up to a black screen. I thought maybe it wasn't compatible as It is a 140w cpu and my old one is a 125w. So I switched it out for my old CPU and I've still got the black screen. When I turn it on all the fans start up, the LED on my motherboard is solid green. I hear no beeps. -I've checked to make sure everything's connected, even unplugged everything and plugged it back in. -I've tested my ram sticks by using one at a time then placing them in different slots. -I've reset the bios by removing the battery overnight. -The monitor works, because I'm using it right now on a backup PC.