Choosing a case is often a purely aesthetic choice. Small and understated cases can be suitable for living rooms, while teenage boys may clamour for big gaming cases with see-through panels and flashing lights. Either way, make sure to choose one to fit the motherboard -we're using an mATX motherboard so a larger ATX case will be fine -and remember to note how many drive bays you need. For a PC with two optical drives and two hard disks, the case must have two 5.25in drive bays and two 3.5in drive bays. Many cases come with USB and Firewire ports on the front, which improve accessibility. We're going to use a Cooler Master Elite 334 case, which uses sound-dampening technology to keep the noise down.