for what I se the dell board is not a bxt and seems to be M-atx form factor , but heres the thing I see is at the back panel , notice how dells board has a space between the edge of its board and the ps/2 port and the giga [or for now true m-atx] the ps/2 port sits right on the edge of the board ??
see with that is it a I/o shield thing with the case or is that a dell proprietary thing and only ''there'' board will fit in there case properly ??
tough call and that's the thing with dell they like proprietary.. and that one little thing may put the screws to you swap ??
''Also, keep in mind that since it is a "manufactured" computer that it will probably only take other motherboards designed by Dell, as they do funky things to the designs of their computers so that they will only take proprietary parts from them''
http://www.computerforum.com/threads/inspiron-570-motherboard-upgrade.210103/