how 'seriously old' are we talking about?
I had a non-OCed P4 2.4 w/ 1.5gb ddr, and a MSI fx5600 AGP
I just built what I would consider a new system, but I used my 3 old WD caviar 80GB IDE HDDs and IDE lite on DL DVD burner and monitors
abit ip35-e, e2180, xfx 8600gt xxx 256mb gddr3, 4x1gb...