Power supply problems can be common in Hewlett Packard
desktop computers, particularly older models.
While it is unsettling to find that your computer will not
power on, it is often a simple problem that you can fix yourself.
Even if you cannot resolve the issue, you may be able to
pinpoint it for the repair technician, thereby saving the repair shop time and
Plug in a lamp to check to that the electrical outlet is live.
You can also plug the computer into another outlet.
Unplug your computer from any power strips or surge
protectors and plug directly into the wall to see if these devices could be the
Disconnect the power cord and any peripherals from your
Press the power button and hold for five seconds.
Plug the power cord back in to see if the computer will now
Disconnect the power
cord and locate the red voltage selector switch on the back of your computer.
Push the switch in the opposite direction and wait five
Flip the switch back as failing to do this may damage the
Plug the power cord back into the computer and electrical
socket, and turn the computer on.
Power up the computer after removing all externally attached peripherals except
for the monitor, keyboard and mouse.
Remove any recently installed internal components such as
video cards, hard drives or memory modules.
If the machine powers on after this, the problem may be that
the added devices need more power than your computer can deliver.
Upgrading the power supply should fix the problem.
Disconnect the power cord and press the power switch.
If it does not operate smoothly, you may need to replace it.
If it functions normally, it may have disconnected from the
Put on an anti-static wristband to prevent static
electricity from affecting the components inside your computer.
Remove the two or three screws on the back of the CPU to
release the side panel.
You will either need a Phillips-head screwdriver or a
flat-head screwdriver depending on your model.
For the entire outer case, you will have at least two screws
on each side and two or three in the back.
Once you have removed these, you will be able to either
slide the side panel off or pull back the entire casing.
Locate the color-coded wires from the back of the switch and
trace them to the motherboard.
If one or more wires have disconnected from the motherboard,
re-attach them manually to the connectors located on the motherboard.