Barebone Mainboard

[Paxi]

I´ve bought a barebone from a friend about 3 month ago. I bought it for just 50$ but he said that the mainboard is damaged. But 50$ for the case is still a nice price and i thought maybe the board still works but he just hasn´t tried all. But now i really tried everything : reset cmos, changed ram, graphic card, cpu and so on.. So i need a new board now if i want to use the barebone. Is there a store that only sells the mainbaord without the case? or could i use an atx board?
thnx and regards