I used to go round repairing Tiny computers under warranty
Got send to one once because the customer said it turned it self off, got there to find it was an ATX machine and when you shut windows down it turned off after, they thought it was a fault because they were used to the older ones where you had to switch it off when you had finished
Depends what board is in it etc. If someone wants a retro system for old games, I only keep Intel or Gigabyte boards, just personal preference but I don't think much to most others, can't remember what boards they used
What Graphics card, PCI or AGP, good spec PCI cards are handy for old machines
Is it old Tower case or desktop?
I was trying to find an old case I could fit the boards I've got, if the case was small enough it could sit ontop of the cupboard at my desk for retro games, but can't find anything right size so will have to use a bigger one and put it at the back or something
What CPU has it got