Always make a point of asking about assembly materials: are all the screws, spacers and other accessories included with the case? A small bag of assembly materials is usually stuck to the inside of the case. Always be wary of cheap offers!

A bag of screws should be inside the empty PC case.

Always make sure you have spacers and mounts to secure the motherboard. A few screws for the case won't hurt either, as they are generally also used to anchor plug-in boards. The screws for mounting drives (hard drive, CD-ROM, etc.) have a finer thread. You need at least four for each drive, but it's always a good idea to have a handful of replacements. By the way, you're barking up the wrong tree if you start looking for these screws at the hardware store. Go to your local computer store - they won't have to look far for the screws you need, and they're bound to be the right size. If possible, avoid plugging the monitor directly into the PC power supply - you're better off with a separate connector. While some power supplies offer an additional plug for a monitor, you'd be well-advised not to use it for screens larger than 19 inches - the high surge at power-up is a frequent source of booting problems.

Ask about the form factor. This depends on the motherboard. Since almost all new motherboards conform to the ATX form factor, your case will have to be ATX compatible. You can still scrounge up AT cases for AT motherboards. A modern ATX motherboard can be identified by the fact that all the jacks for the keyboard, mouse, parallel printer, and serial COM port are soldered directly onto the motherboard. We'll document this in the section on the motherboard.