Try turing off QoS settings for the router if they are on.
Open a web browser, any will do and go to 192.168.0.1 and log in to the router. PW is blank if you haven't changed it. This needs to be changed at some point.
Ensure that Primary and 2ndary DNS IP addresses are filled in under Setup/Internet/Manual section of the router.
Are you using the Wireless to connect to the internet?
What wireless modes are you using?
Try changing the wireless mode from mixed to single mode G.
If you need some help, we might be able to remote into your system and help you out if you can't seem to find the places you need to go. Hope you can get it setup.