My shortest answer is... Install Linux.

"I would also like to run a webpage, preferably with a .com URL. The only thing I can't seem to understand is how to change the IP Address of the server to something like CNET.com"

Look up DYNAMIC DNS on google.com and godaddy.com

In closing, MOST ISP's will disable/block port 80 to stop people from running a web server since it could be a big load if everyone did. Other disincentives are caps on byte transfers and that agreement you made to get service.

Bob