i found some used HP PCs that have intel CPUs in them and some good HDD and SDD (i need that for my gaming PC). one of them is HP 8000 elite with a C2D E7500, 4GB DDR3 ram, some HDD and SSD and a useless PSU. What i'm worried is it's motherboard which is obviously very old and i'm not sure if it can run newer cards (like rx470 or gtx 1060) i think it's a Q45 mobo.
for now i just want to mine with one GPU (most likely a gtx 1060 6gb as Zcash seems very profitable right now)
and i don't care about the PSU and and the case, i'll get a new PSU and build my own case.