| Cases Computer Simulations | Tapes | No tapes | No books | No hardware |
| CDS Micro Systems | Tapes | Tapes sorted by code | No books | No hardware |
| C. Jefferies | No tapes | No tapes | No books | No hardware |
| CP Software | Tapes | No tapes | No books | No hardware |
| Cambridge Technology Group | No tapes | No tapes | No books | Hardware |
| Calpac Computer Software | No tapes | No tapes | No books | No hardware |
| Cambridge Microelectronics | No tapes | No tapes | No books | No hardware |
| Campbell Systems | Tapes | No tapes | No books | No hardware |
| Capital Computers | No tapes | No tapes | No books | Hardware |
| Caps | No tapes | No tapes | No books | No hardware |
| Carnell | Tapes | No tapes | No books | No hardware |
| Cascade | Tapes | No tapes | No books | No hardware |
| Cheetah | No tapes | No tapes | No books | Hardware |
| Cheshire Micro Design | No tapes | No tapes | No books | No hardware |
| Cobra Technology Limited | No tapes | No tapes | No books | No hardware |
| Collins Computing | No tapes | No tapes | No books | No hardware |
| Colourmatic | Tapes | No tapes | No books | No hardware |
| Comprocsys | No tapes | No tapes | No books | Hardware |
| Compshop | No tapes | No tapes | No books | No hardware |
| Compusound | No tapes | No tapes | No books | No hardware |
| Computatutor | No tapes | No tapes | No books | No hardware |
| Computawine | No tapes | No tapes | No books | No hardware |
| Computer Keyboards | No tapes | No tapes | No books | No hardware |
| Computer Rentals | Tapes | No tapes | No books | No hardware |
| Computers for Education | No tapes | No tapes | No books | No hardware |
| Computertutor | Tapes | No tapes | No books | No hardware |
| Computex | No tapes | No tapes | No books | No hardware |
| Control Technology | Tapes | No tapes | No books | No hardware |
| Cosma | Tapes | No tapes | No books | No hardware |
| Creative Computing Press | No tapes | No tapes | Books | No hardware |
| Crystal | Tapes | No tapes | No books | No hardware |
| Custom Cases | No tapes | No tapes | No books | No hardware |