A. Please look for the specification ”Motherboard Configurations” of the particular chassis on this website. If you have a ATX motherboard it will supported by only ATX chassis. If you have a microATX motherboard, then it can be installed on both ATX as well as microATX chassis. The mini ITX motherboards can be install on all the chassis be it ATX, microATX or ITX.
There are following types of general motherboards.
Extended ATX (E-ATX) : 12” x 13”, (305x330mm) Mainly used for servers.
Standard ATX : 12” x 9.6”, (305x244mm) Standard home, game, office PC
MicroATX (m-ATX) : 9.6” x 9.6”, (244x244mm) Smaller than ATX, used in home, office PC.
Mini-ITX : 6.7” x 6.7”, (170x170mm) Used in very dedicated PCs as HTPC, Car PC etc.