If you arrived at this step and you computer isn’t turning on yet, this means that one of the components from your PC is defective, and you need to find out which one. If you followed our guide correctly, your computer now has only the following parts installed:

• Power supply
• Motherboard
• CPU
• CPU cooler
• One memory module
• One video card

You will need to test each part on another computer that you know is working correctly. You will need a computer with the same CPU socket for you to test your CPU and with the same memory type for you to test your memory modules. For most users this is the hard part, as most people don’t have two similar computers at home. You will need a friend with a similar computer. (This is a terrific time to call that cousin who is always asking for favors from you.)

You will get your video card, install it on this other computer (removing the video card from this other computer first, of course), turn it on and see what happens. Don’t forget to test all the parts, as more than one component may be defective. Also, don’t forget that you can only install and remove parts with the computer turned off, and for extra precaution, we recommend that you do this with the main power cord removed from the wall.

After this step, you will have isolated which component is defective and that must be replaced.