Second of all here are the links so you can check if they are specifically compatible:
Motherboard: ASUS M4A785-M http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=5235299&sku=A455-2881&srkey=Asus%20M4A785-M
Case: Cooler Master Elite 330 Black ATX Mid-Tower http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2541413&CatId=1842
PSU: Silverstone Strider ST50F ATX 500W http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=4435016&sku=S35-1216&srkey=Silverstone%20Strider%20ST50F%20ATX%20500W
NOTES: With the PSU, i will use a european power cord with it since i live in europe and it doesn't have a voltage switch. For more specs on the hardware, go down on the website untill you see a box that says "Detailed Specs".
Yes, the mATX motherboard will fit in the ATX case with the ATX PSU.
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