Do you have a static IP?

If you don't have static IP, even you install a web server, it is not convenient to allow people to visit your web sites on your web server, because the IP will be changed each time you re-connect to the internet. You have to let your friends know your IP, if your IP is changed.

Anyway, to be a web server, it does not needed to be dedicated. You still can use your computer as you usually do. You just need to install a web server.

For win2k, there is IIS -- internet information service will be installed by default.

If you don't have win2k, such as win98, or xp home edtion, you may install Apache web server (window's version), there are bunches of web servers you can get by free. but Apache, and IIS are very popular.