Checking the power source Power supply fan is noisy or having interference Power supply light does not turn on or power supply fan does not spin Testing the power supply separately from the system Power supply light is on and flashes Ordering a replacement power supply This document pertains to HP and Compaq desktop computers. Figure : Power supply light If the small light on the power supply does not turn on and the fan in the power supply does not spin, and it looks like there is no power, see Power supply light does not turn on. If the small light on the power supply turns on, see Power supply light on or flashes. Computer Does Not Start (Windows 10, 8) Windows 7 Does Not Start Computer Does Not Start (Windows Vista) Resolving Startup Problems (Windows XP, Me, and 98) Checking the power source Figure : Power supply vent If you have tried all of the previous steps and the power supply light remains off, use the steps in the next section, Power supply light comes on or flashes, to reseat the cables and check the power switch connector.

If the power supply fan spins when the computer is turned on but the light does not turn on, see Power supply light comes on or flashes. Figure : Commercial PSUs Figure : Consumer PSUs Figure : Example of common power connections If the LED is on solid If the LED is still flashing If the LED light is now off Figure : Find the Spare Number or Part Number If the part number is not listed on the power supply or is unreadable, follow these steps to use the HP PartSurfer website to find a list of power supplies that are compatible with your computer. If you use a power supply that is not listed on HP PartSurfer for that computer as a replacement, you risk voiding the computer’s warranty or damaging the computer. Open the HP Parts Ordering website (in English). If necessary, select your country/region and language in the upper right corner of the page. Figure : Example of a power supply part listed on the HP Parts Ordering website Every AC unit is designed differently and some AC units are not compatible with the smartAC kit.