If you are not familiar with the components with building a computer, maybe you should look into someone doing the deed for you.
Here is a list of the components that every computer should have:
- Case (with a fan)
- Power Supply (at least 300 watts)
- Processor (AMD or Intel)
- Motherboard (make sure processor and motherboard match)
- Hard Drive (80GB+ is preferred)
- Memory (512MB+ is recommended)
- Graphics Card (can be between $100 and $800, also can be on-board (on the motherboard))
- Sound Card (can also be on-board)
- Case Fan (to exhaust heat/bring in cool air)
- CD-RW/DVD-ROM drive (either cd burner/dvd burner or just a dvd-rom)
- Floppy Drive (many computers now do not include floppy drives but they are about $8 and you might use it)
- Monitor (LCD Flat panel or CRT, CRT's are cheaper but bulkier)
- Keyboard/Mouse (obvious)
- Operating System (i recommend Windows XP Pro instead of Home)
- Speakers ($10-$300; price varies depending on size, 2.0, 2.1, 4.1, or 5.1 system)