Issues with new router Dlink DGL - 4500

Couple issues im having with the wireless connection I have a Dlink DGL 4500 1) Losing connection to my lap top....same room, built in card. 2) Dads computer upstairs wont validate so it wont get online. 3) Toshiba A3 HD DVD wont connect to the internet again, it did when i had to run firmware update. Can someone help me solve these issues.