Okkies.. clearing some stuff up..
1. Make sure that you have your 'encryption' methods and keys set on ALL machines. (They MUST use the same 'key' as the router.. otherwise, they won't have proper 'access'.. which won't let the machine connect to the router.)
2. Check your network configurations.
Look at your wireless connection settings.. check the ip address of your machine, to see if you have a valid connection. The ip address will appear under the 'details' menu on the left side of the screen. ^.^ An address of '0.0.0.0' means that there is no connection present. Depending on your router's configuration, your ip should have the first three subnets of your LAN.. ie. 192.168.0 (or 192.168.1, etc) the ip of the router will ALWAYS be 192.x.x.1. The ip of your machine can be anywhere between 192.x.x.2-254 (0 and 255 aren't used.)
3. Type '192.168.0.1' (or 192.168.1.1, etc..) until you get access to the router.
(Easier than remembering a dynamic ip, which can change at any time. -.-)
4. Make sure your router's settings are properly setup.
(If you don't know what something does, leave it alone.)
That's all you should need to do..
~~Azurith