Who knows what a an MN-500 is for heaven's sake ? Well, I do now having Googled it.
Start by finding the manual, from Microsoft's website (or read it if you already have it). You can set up both the WAN (the link to the outside world) and LAN (stuff like wireless) without the disk. The WAN settings may involve some help from your internet provider.
But to do the LAN part here are some basic tips.
Connect the computer to the router with an ethernet cable.
See the pages in the literature which came with your router for how to access the user setup screens in the router. Once in go to wireless security and review or renew the wireless security type and password. WPA PSK TKIP is the most common security type in use. Make a note of the SSID or change it to one of your invention.
Go to wireless mode and ensure that it's set to a protocol matching your computer's wireless adapter (mixed mode is a safe bet).
Disconnect ethernet cable.
Go to the computer's wireless networking setup screen and see if you can detect the router's SSID (wireless call sign). Select that network.
Apply the wireless security type and password to the computer's wireless networking setup screen.