I want to secure my Belkin 'n' wireless router . I am running Windos XP, Windows Vista, Windows 7 and Mac OS Snow Leopard. How can I do this?

Connect any one of the computers to the router with a ethernet cable. open internet explorer, clear out the address bar on the top, and type 192.168.2.1. when u hit enter, u'll get a router set up utility. in this page u'll have an option -security- below "wireless". when u click security, it'll ask for a password, leave it blank and hit submit. on the next window, choose the option WPA/WP2, then u'll have some more options, look for PASSWORD(PSK).. put in a password which should be 8 to 63 characters long, its case sensitive. click on apply changes.

This type of problem fixed in simple steps :
1.type 192.168.1.2 in the top of browser
2. type username and password and access the router setup page
3.go to wireless settings and change the password for more help contact belkin Services i hope this will help you ..thanks

Is there any computer connected to the router ?
If not then you will need to connect the computer to the router.
check the IP address of the computer.
open the router set up page of the router.
Here you can change the wireless settings of the router.
Click Here for step by step instructions

Logon to your router and go through the wireless set up to set a passphrase and turn on the encryption (WEP , WPA WPA2 etc)

to logon you need to enter the routers ip address into your web browsers address bar usually 192.168.1.1 then a username and password to logon

once set up all your other systems should detect the network and prompt you for the pass phrase.

all the details you need including the manual are here:
http://en-us-support.belkin.com/app/product/list/q/routers/

Get inside the router by typing the router address in the browzer.

Go to wireless setup or wireless tab / select wireless security / select the type of encription u want / enter ur password and save the same.

Then go to the administration tab and change the routers default password and save it.

Ur done and secured.