Moving components into a new case

[Olli128]

Hi, I have a Dell 560 that I upgraded with a radeon 6770 and bigger psu a while ago. What I want to do next is move all the components into a new case but I'm having trouble working out what I will need. I know that the motherboard in a dell wont screw into normal ATX or MicroATX cases, so I will have to replace the motherboard. Can anyone help me choose a new motherboard, hopefully keeping the old CPU (AMD Athlon ll X4 635). Also, can I use the old hard drive still and would I need to do a clean install of windows?

Thanks

 

[Olli128]

Cant edit for some reason, forgot to mention that I'm looking at the Coolermaster HAF 912 Plus case