I need help!!!!!

I am trying to set up a pc, along with a Wi-Fi signal booster. Got the booster working with wifi, then got booster working with pc, now cannot connect to internet? Its an XP machine, a Wireless-N WiFi Repeater.
I am using the repeater as the router is on other side of house and signal drops out where pc is.
I have followed instructions that came in the box but its still driving me crazy, If anyone can suggest something to help, it would be fab!!!!!!!