What size motherboard is mine? (e.g., ATX)

Cowtastrophe

Honorable
Aug 8, 2013
27
0
10,530
Well, i'm not very familiar with the whole motherboard shabam, and I'm looking to upgrade my case. I have a Dell Studio 540 with an Intel Core 2 Quad and a XFX 7770 Core Edition (even though I know that doesn't matter) in a Dell Studio 540 case. I'm looking at standard ATX cases, but I don't want to waste money AND time on something that might not even work for me. So please, any help would be appreciated. My birthday was just on Saturday and I got a good amount of money. I'm still looking to not spend too much. $75 at tops. Some cases I am looking at:

http://www.newegg.com/Product/Product.aspx?Item=N82E16811108433

http://www.newegg.com/Product/Product.aspx?Item=N82E16811553014

http://www.newegg.com/Product/Product.aspx?Item=N82E16811156063

If you can't find what my motherboard looks like here is a link to it:

http://www.ebay.com/itm/DELL-STUDIO-540-540S-OEM-IPIEL-RN2-MOTHERBOARD-M017G-N627J-CN-0M017G-CN-0N627J-/251258771953


If I chose the wrong cases, I would GREATLY appreciate any recommendations, and any help would also be greatly appreciated. Thanks! :)