Wireless Router. I have just bought a netgear wireless router and tried using the wizard tutorial

Question

I have just bought a netgear wireless router and tried using the wizard tutorial to install it but it only half instaled the wireless which was fine and it worked but it was an unsecure internet connection which meant that anyone could use the wireless if they were in range of out computer. So i tried to reinstall it so that i could add the security option but now the wireless will not work at all.