I live in an apartment with two other people, and we want to network our computers together for the purpose of file sharing. We want the option of adding computers (notebooks) on the network wirelessly, so at any given time there will be between three and five computers on the network.

Because our DSL modem is already wireless, we have wireless access, but we want a file-sharing network. Can we do this without a router, or do I need to buy one? If I buy a wireless router, will it conflict with my wireless DSL modem?

You may be able to share files by simply turning on File and Printer sharing on your notebooks, and then using the wireless LAN connectivity the DSL modem provides to connect to each other.

Sharing files in workgroup mode requires that each computer have a local account for each user who will connect. If you take this approach, you can toggle the Windows firewall settings to block file sharing when you are not using it.

A router could provide an additional security boundary between your apartment and the Internet but might not be required. If you add a wireless router to the network, you will need to configure the router and the DSL modem wireless access point to communicate with each other.