Well considering I am using amd athlom 64 (single core processor ) for mining (4 gpu rig )so you can most likely convert it to a mining rig .
But my advice stay away /sell/ scrap this as you are gonna face a lot of problems and you will have to figure them out your self as no one has this old equipment lying around .
Minimum Budget for mining :
is around 150$ + the Graphics cards and Power supply you are gonna use.
the most expensive is the graphic cards and power supply if you want to build gpu rig because one graphic cards is almost $200 or more if you want to buy high end vga cards. without good vga cards, you can not mining with big hashrate and the algo selection is not much. I think you need big budget to build your own mining rig with vga cards.