Fit a whole PC in a ps2? yes, I've seen youtube videos, but I don't think there's room for a graphics card/power supply.
Flex PSU, Integrated GPU, G4400 or something like that and a Mini-ITX motherboard and throw in a 2.5 HDD. I'm gonna try it.
Take plenty of pics!
You can do it with a PS3, and depends it on which version of the PS2 you have OG or the slim one.
I have the fat one.