First if you know the IP address of the router I guess it will be 192.168.0.1 by default or else get it from command prompt C:IPconfig/all the default gateway is your router IP address and DNS address. And the
After that go to network connections of PC and Laptop. For PC, Right click on Local area connection--> properties--> From the list of connections select Internet Protocol(TCP/IP) ,Click properties---> In general Instead of "IP address automatic" Select the "Use the IP address selected" And put the IP address that you want between range 192.168.0.3 -192.168.0.254 (assuming that your router is 192.168.0.1). Subnet mask as 255.255.255.0 and Gateway as your router IP address. Put the DNS address which you found from command prompt , Usually this will be your router address as well.
For the laptop right click wireless from the network connections.Follow the same steps described for PC.
I am not sure about the XBOX but I think there will be control panel for it as well , where you can do the above settings.
LIFE is so simple, if you know the reason of your existence at certain place. Treat every step as first one and trust god, friends, relatives and everyone.
Its a simple magic trick given to me by one friend also and I am at this stage