Question Easiest way to test individual components?

[NeoConstantine]

My computer has a problem. It will turn on, but it won't boot. It's not a problem with my graphics card or monitor, so I'm pretty stuck. I've tried everything I could think of, short of testing each component individually. It's not like I have a bunch of free CPUs lying around the house, which would be the brute-force method of testing. I noticed there was some weirdness with the PSU fan, it would only do a quick little quarter-spin when I turn the computer off, but I don't know how to be sure that's actually broken instead of my PSU not needing cooling yet. I'd like to test it, but on what? I don't have money to throw around.

 

[DSzymborski]

How do you know it's not a problem with the graphics card if you can't test component individually?

A good place to start would also be giving us the full specs of your PC and the history of the problem. Just knowing a mystery PC won't start doesn't really provide anything to go on.