Don't waste your money on another HP 2/3 size junk PSU. I had the same situation with my neices PSU in her HP. Get a new case and a real PSU and move everything to the new case. I got a quicky ultra budget one from Comp USA for $29 a few years ago when this happened. The PSU hadn't actually failed either, it was just eating HDs. I'm sure you can find a cheap one or maybe a better one that can be reused later for a new build.
It's the easiest and best way in the long run.