ECS P4M800PRO-M VIA P4M800 Pro LGA 775 (Socket T) micro ATX

The motherboard or mainboard is the component that connects all the different parts of your computer. Often it has some integrated components like a sound card, enabling your computer to play sound, or a network card, to connect your computer to the network. The standard form factor (size) for motherboards is ATX, you need at least a midi-tower to fit one of those in. Micro-ATX motherboards are often more complete and have more onboard devices, like a video board and fit in smaller cases, but are generally less expandable.