Why does my PCs PSU keep breaking?

This computer is old, so many of the OEM parts are near the end of their life. They’re all going to die at some point.

Unless you need the OEM unit for a specific reason (which is *highly* unlikely, but not out of the question knowing how much Dell loved proprietary parts during this era) you’re better off getting a good 3rd party Seasonic or Corsair to replace the failing OEM supplies for good. There may be a case gap as this was still somewhat into Dell’s adventures into BTX, but a standard ATX unit should fit without any case modifications.