Ahh, I see that now.. the motherboard has a form factor ATX..
Other than the technical features of different form factors, picture ATX to be bigger than Micro ATX.
If your board is too big, it will not fit in the case therefore you can't use it.
I'd call Dell and find out what kind of form factor the case is..
EDIT: Upon doing some research, the case is a Micro ATX form factor..
So, the second board he posted will not work.