Here's the scoop: I've got three PCs. I pull this off by treating my components well, then when I upgrade one, I pass the old part down to the next PC, and the one in there to the next. It keeps things running, although by the third PC, things are way, way out of date. The stuff in the third PC is probably more than ten years old at this point, and is normally only used to feed videos to the TV (and some HD videos still won't play in it.) Part of the problem was that my last video card upgrade was the result of a failure, so there was nothing to pass down, and it will be a long time before I can upgrade again.
The issue is that my kids and I have been playing Borderlands in co-op lately. We've all had more fun doing this together than we've had from gaming for years, and really want to continue. I've been using the TV PC to let one of the kids play. It only runs by cranking down the resolution and turning off pretty much every graphical feature, but it runs. Once we finish, though, we won't be able to continue with the series. Most gamers wouldn't actually call the way it runs Borderlands 1 'playable' (but don't tell my son!) It is unlikely it would even launch BL2.
So, I'm trying to upgrade that PC to meet the Borderlands 2/Pre-Sequel recommended system requirements. Since I now have a video card (and I had a case, power supply, and drives waiting), I just need a motherboard, processor, and RAM. The recommended specs for the processor are simply "2.3 GHz Quad Core processor." I've been looking around, and haven't had much luck. It seems that very few places keep anything older than a year in stock, and anything newer than that is way out of my budget. Craigslist is useless around here (not enough people nearby), and I'm really, really hesitant to trust ebay for older hardware, having been burned in the past.