i have a shitty winme computer downstairs where the cable internet is located. i am thinking of buying a pc for upstairs, and want to share the internet with a wirelss router. i have read that wireless is only for windows 2000/xp, so i was wondering, could i have it hooked up so it is wired downstairs but broadcasts the signal upstairs? also how well would it work, its about 10 feet up and 15 feet across when you get to the second floor.

Wireless is not only for XP and 2000. Wireless will work under any operating system. You only need to worry about the drivers for the wireless card/adaptor in the PC.

Whoever ways that you cannot set up wirless on all windows operationg systems above 98 SE (because I haven't tried below that) is messed up.
Wireless will work on any os, just make sure that it comes with the drivers.
Also, it is good to be wireless at that short of a distance but it will make your internet connection a little faster if you just connect to the router / hub / switch directly.
Wireless likes to be difficult at sometimes, from the WEP (encryptions) to the setting it up.
I would go wired but thats just because I have set up too many wireless networks and had to deal with all of those things so much.