Need some help on the Ole Epic 4G

I got a Epic 4G from Sprint and I've been using it as a "gaming" phone. Just sitting around by my bed.

So I rooted this thing YEARS ago and I don't even recall what I rooted it with. But Right now, it's having serious issues and it looks like I need to do a fresh install of android.

So I don't even use it for making phone calls and it's connected to WiFi.

Can someone please advise on what I I can do? Much appreciated.