@Adam Moore3/">@
@Adam Moore3, just because it's a 775 socket doesn't mean you can just slap a dual-core in there; some of those old boards only support single-core Pentiums or Intel Celerons...
The PC in the title is pretty ancient and uses that same 775 socket, though I guess it’s slightly saved by having a faster chip and DDR3 RAM. I don't know what kind of stuff your kids are into, but if they eventually want to play some games, maybe it wouldn't be a bad idea to save at least $667 toward a much better, modern setup. This one is just old and a total pain to upgrade.
It might be worth checking out the motherboard in the current rig; you could probably swap in a faster processor for $33 and maybe throw in a used or new SSD (new ones are around $100).
If you do end up buying the PC from the title, you should definitely move the current graphics card over to it.