Mobo upgrade for Dell Optiplex 755

Solution
Mini Tower is BTX Form Factor, which was short lived. You can read about it in the Wikipedia. Retail boxed motherboards don't use that size anymore. ASUS H61M-K LGA 1155 H61 Micro ATX Motherboard, which is why I suggested getting a different PC case.
http://en.wikipedia.org/wiki/BTX_(form_factor)
Mini Tower is BTX Form Factor, which was short lived. You can read about it in the Wikipedia. Retail boxed motherboards don't use that size anymore. ASUS H61M-K LGA 1155 H61 Micro ATX Motherboard, which is why I suggested getting a different PC case.
http://en.wikipedia.org/wiki/BTX_(form_factor)
 
Solution