I'd guess the second pc is about 6 to 7 years old.
I have an old P4 3,2 GHz HT at home, the fastest Intel processor at that time. Apart from using a lot of energy and hard drives (already killed 2 of them), it is pretty slow.
Still, you could still use it as a server, for example running Ubuntu or something like that (if you don't care about energy consumption). Around here, you would probably just bring it to the collection station.