As LH2 says, you must have "Client for Microsoft Networks" installed to "see" MS network resources.
It's Start -> Settings -> Network Connections -> "Network"
Also, for the laptop to be "seen" by the rest of the network you must have "File and Printer Sharing for Microspft Networks" installed.
You DON'T have to have all computers in the same Workgroup (tho' it helps with passwords) to access resources on other PCs.
SD