Fixing your PC can be a complicated process, because of all the things that might go wrong. Your storage drives may be failing, the RAM may have gotten glitchy, the computer may have overheated, there may be an electrical short in the case--it's a long list. If your computer is under warranty, consulting the manufacturer is generally better than trying to fixing it yourself. If you are not experienced with hardware maintenance, deferring to a techie friend is generally better as well.
Checking Cables
Let's take a look at the basics before we break out the toolbox. Check your cables to make sure they are connected and secure. Ideally, your computer should be plugged into a surge protector strip instead of the AC outlet, so check the power strip to make sure it has not been switched off accidentally. Check the switch on the back of the power supply or CPU that sometimes gets bumped into the off position when you move the case.
Motherboard Beep Codes
If you turn on your computer and get a series of unexpected beeps, your motherboard is communicating issues. Consult its documentation for a translation of the "beep codes." Certain codes translate to defective RAM, a disconnected CPU (central processing unit) fan cable, or a disconnected hard drive or failure to recognize the monitor or video card.
Internal Cables
Open the case with the computer powered off and visually inspect its cabling. If you have just installed a new video card, it will probably have an internal power plug that must be attached to the power supply. Also take a look at your RAM "sticks" and your video card. If their contacts look slanted, then they are not properly seated. Video cards and RAM will click into place when they are attached correctly. Hard drive data cables can come loose because of all the vibration in the case, caused primarily by fans.
Loose Screws
Check for a loose screw by tilting the case around and listening for a rattle. If a screw is touching both the motherboard and the case, this will cause an electrical short (which is why a motherboard's "risers" are made of brass or plastic instead of steel, since those don't conduct electricity). Loose screws can usually be removed by tilting the case around until the screw settles on the bottom, then retrieving it with a pincer tool. Magnetic screwdrivers are handy, but they can corrupt data on your hard drive if placed closely enough.
Verifying Functionality
If everything is in place, turn the computer on. Verify that the case fans and CPU fan are active. Place your hand outside and behind the power supply unit (PSU). If you don't feel a breeze, the PSU fan may be faulty. If these non-functional components are plugged in, they need to be replaced.
Tags: power supply, video card, your computer, case around, electrical short