No Im not sure, its just a cheap place to start, or you could test it with a multi-meter. if you want to reformat and it isnt going to cause you a long time to reinstall, that is up to you. Before you did that I would ask if there was anything you installed hardware or software prior to it acting up.
Heres a video on testing it, I didnt watch it in its entirety, but testing a psu can be tricky as with a multimeter you need to put a load on it for it to be accurate, however if your voltages are of by more than 20% that would usually indicate a bad psu.
https://www.youtube.com/watch?v=ac7YMUcMjbw