Setting Up a LAN

Hey guys,
I live on dorm... meaning each one of my components randomly gets assigned an IP address when connect to the network. I have a router with my Xbox, PS2, Desktop, Laptop, and External Hard drive hooked up to it.
I've changed the workgroups on my two computers and my drive to "bob" but my computers still cant find one another. My laptop can talk to my hard drive (from an old connection before I came to school), but when I click on the "view computers in this workgroup" tab it takes forever to load than says I dont have the privileges. when I do the same on my desktop it opens up and shows only my desktop. I also use syncable desktop... well try to use it, but I cant get my two computers to "talk to each other" and btw my laptop is a netbook so my goal is to share my desktop's DVD drive. I already set it to share... but I have to get them on the same network first. HELP lol thanks