The style and size of the computer Case various. The three main classifications are tower, desktop, and baby tower.

Baby tower/Desktop is small case and fits only few optional components. It fits small motherboard, few pci slots or ports, and one external drive.

Tower is tall and large enough to hold the maximum number of hardware components with better airflow than desktop case. If you need to install 2 or more external drives and large motherboard that supports extra ports for upgrade, this might be your choice. Towers vary in size, there are mini-tower, mid-tower, and full-tower.

Desktop vary in size and style but are flat and wide and normally support 1 or 2 external drives. Some desktop cases are large to support large motherboard with extra expansion cards when others might support few expansion cards.

Power supply is the sub component that supplies electric power to your system. It's the power engine of your computer. Your PC Chassis may come with pre-installed power supply but it's best to get power supply that is capable of providing enough power to the system. When selecting your power supply, do a research and buy power supply that provides efficient and stable power with genuine manufacturer label.

Before openning your case, we recommend that you put on an antistatic wrist strap to prevent electronstatic discharge dammages to the circuite.
1. Open your case by removing the screws or mounts.
2. Remove if there is pre-installed power supply.
3. Insert and mount your new power supply in the power supply bay. Make sure your power supply is properly mounted.
4. Connect the power supply to the motherboard. (Your power supply should have 6-pin for Baby AT-Style or 20-pin ATX-Style connection).
5. Connect the power supply to the drives. 6. Make sure all the connectors and mounts are installed firm.