Bad PSU or bad HDD?

[merlin2oo2]

Hey guys,
I'm 99% positive that my hard drive the the source of my recent computer woes, but I'd like to also check the PSU. I don't have a multimeter, but the PSU box feels pretty warm at times. It's a Corsair 550w, about 3-4 years old. Is there a way to check if it's operating properly without a multimeter?

 

[beenthere]

Do you fans run when you boot the PC? A multimeter can tell you voltage if the fans run when you boot up.

 

[merlin2oo2]

Fans are running just fine. Given that my hard drive is probably pushing 10 years and failed a S.M.A.R.T. test for Reallocated thingies(technical term, I swear!), I'm pretty darn sure that's the problem and not the PSU, but I had read that bad PSUs can kill hard drives(among other things). I just want to be sure that I don't inadvertently fry a brand-new hard drive because I misidentified the true source of the issue.