My grandmother has a Dell Dimension 4500S it was working very well but a few weeks ago start acting crazy. When I turn the power on, the machine boot-up ok, but after the windows XP logo appears the display goes blank and then nothing else happens, the lights on the back of the machine are ok (all green) I did try the hard drive in another computer and it works ok, I try another power supply same thing happens, this machine uses a integrated video card so I couldn’t check that, but I think it is nothing wrong with the video since goes thru the cycle, also I enter set-up and I can read everything in the display, what else could be wrong?. The other day when I test the hard drive after I put it back, the machine boot-up ok but after I turn it off and on again same thing happens. I try to move the wires to see if anything is loose but not results I never encounter a problem like this. Can somebody help???