Problems Problems Problems with a HP XG814!!!

[weatherman]

Computer would lock up all the time when starting up. I get to Windows Desktop, it makes the startup sound, then it locks up. Nothing else loads. Also, The CD-ROM Drive would not work ethier. I took the computer apart, put a different CD-ROM in, and the computer wouldn't power on. I looked inside it to see where the problem is. I found a power cable, plugged that in inside the computer, I plug in the computer itself, it turned on automatically, and would not turn off pushing the power button. I had to ethier unplug it or turn off my surge protector to get it turned off. I also hooked up my monitor, keyboard, and mouse, and I turned on the monitor, turned computer back on, but now, nothing will come up on the monitor at all. I can't find the problem. I found a wire that was loose. It was blue, yellow, and had 2 black on it. It's 4 plugs. I need help as soon as I can to solve this issue. In the old CD-ROM Drive, it would open or close, but would not read discs. Also inside the computer, there was so much dust in it.