OK, basic system for office-type use/internet...this is what I'd recommend off the top of my head:
1. CPU - AMD Duron. These have an excellent Price/perofrmance ratio, and it looks like the current motherboards will probably support the future AMD CPUs.
2. Motherboard - I recently put together a basic PC using an ECS K7S5A motherboard that worked very well. I'd recommend looking into a fairly intergrated board (AC97 sound or better especially) as it makes life easier. I would, however, think carefully about integrated video. Perhaps if the PC is only going to be used for office apps this won't matter, but most integrated video is horrible.
3. RAM - DDR is better, but PC133 may be worth looking into. I'm not sure how big a performance hit you'll take by going PC133 over PC2100. I know when I build a basic PC the cost wasn't really justified IMO (plus, the motherboard I used could take either DDR or PC133, allowing them to upgrae to DDR later if they felt like it).
4. Video - not really sure. For office apps alone antyhing modern will probably due. If interested in light gaming, check out a GF2MX-based card.
5. Hard drive - for a budget, I think any of the newer 5400 RPM drives will probably due fine. But the cost for a 7200 RPM drive may not be that large, and appreciated in office apps. Since you're situation might be very cost-sensitive, and I have no idea how much space you'll need, I'm not going to recommend a specific drive.
6. Other....I wouldn't spend too much on the latest and greateest CD-ROM, since it'll probably rarely be used. A burner might be nice, but I have no idea if your situation needs it. A nice case is always nice - I'm not sure what good yet cheap midtowers are out these days.
Hope this helps!
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