8Solutions - Your PC Turns on But No Display. Test your monitor. Make sure your computer has completely restarted. Verify that the power supply voltage switch is set correctly. Perform a hard reset. Clear the BIOS memory. Reseat the memory modules. Understand LED lights. Check Hardware. Astitle says, I bought a be Quiet power supply to replace my old one. Bet I'm forgetting something or some cable but I can't think what. On mobile so bear with me. Motherboard cable: check CPU cable: check Satas to HDD : check VGA: check There's this weird cable that I don't recognise that was plugged in the old one. It uses a molex cable. Didnt do anything to it if that's what you mean. We replaced the mobo with an exact new one. Since it's new I'll consider it's bad as one of the last resort for a refund. The old mobo with a new PSU didn't turn on at all. With this new Mobo it at least has a green LED light on it and turns on for a short second before the fan turning off. Ifpower is out completely, those won't work as well. Check the power connection to the PC. Make sure the cable is not lose. Also, make sure the power connection is working by testing it with another electronic device. PCs have a power on/off switch on the back usually. Make sure the switch is in the on position. Step2: Connect! Now it's time for the wire. Bend the wire and close up the little green plug from the big ATX plug to any other BLACK plug. Cause the black is the ground. To come off best you should connect the green with black besides the green. Your PSU should power up immendiatly! You are done! isn't good for the PSU. Next double-check the cables for both the monitor and the computer. Check the power cable for the monitor and verify that the outlet from which it is getting electricity is supplying power to other appliances or devices. If the power cable is on a power strip, you might need to double-check and make sure that the power strip is turned on. Important Make sure that you have no power connected to the computer for about five minutes with the battery removed before continuing. 6. Reconnect a keyboard, monitor, and mains power. Plugin your keyboard, the monitor's display cable, and mains power cable to the computer. Make sure the power is turned on. 7. Press the power button RAMand Power Supply Support [SOLVED] Computer not turning on. 1658 Views 5 Replies 4 Participants Last post by Stu_computer, Apr 25, 2011 Jump to Latest S. Smokey57 Discussion Only show this user. I want to re-activate previous thread:-Computer not starting/booting The motherboard is an ASUS P45800-MX using Windows XP SP3, about 1.5GB WHICHfan are you talking about? A case fan, the CPU cooler, the fan inside the power supply? When you turn the power on, does the fan inside the power supply turn on and stay on, or not? Likely the problem is simply a faulty power supply, since those VS series Corsair units are not very good to begin with. Its actually a Mac Mini 2011 i5 2.3GHz she used the wrong power cord on. The day before the computer was working. Then the next day after she plugged it in it stopped working. Meaning, the computer did not start up when she used the incorrect power cord. We tried the correct power cord, but nothing, no start up. GLxuIz.