The main parts
| Part | What it does |
|---|---|
| CPU (processor) | Runs instructions. The "brain" |
| RAM (memory) | Fast temporary workspace for programs currently in use |
| Storage (HDD or SSD) | Permanent storage for files and the operating system |
| Motherboard | The main board connecting everything |
| PSU (power supply) | Converts mains power to the voltages parts need |
| GPU (graphics) | Draws images and video, and speeds up graphics work |
| Cooling | Fans and heatsinks that stop parts overheating |
RAM vs storage
RAM is like a desk: fast, but cleared when the computer turns off. Storage is like a cupboard: slower, but keeps files. An SSD is much faster than an HDD and is the best upgrade for an old, slow computer.
Common ports and connectors
- USB for keyboards, drives and phones
- HDMI / DisplayPort for monitors
- Ethernet (RJ45) for wired networks
- Audio jacks for headphones and speakers
- Power connector
Common hardware problems and clues
| Symptom | Possible cause |
|---|---|
| No power at all | Power cable, PSU or socket |
| Beeps at start | RAM or graphics card not seated properly |
| Very slow computer | Old HDD, low RAM, too many startup programs |
| Overheating and loud fan | Dust, failed fan, dried thermal paste |
| No display | Loose monitor cable, wrong input, graphics issue |
| Unknown device errors | Missing or wrong drivers |
Safe handling
- Switch off and unplug before opening a computer.
- Touch a metal part of the case to discharge static electricity, or use an anti-static wrist strap.
- Hold cards by their edges.
- Take a photo before you unplug cables so you can put them back.
Practice
Open your device's system information (on Windows, search System Information) and write down the CPU, RAM and storage type.