Xbox live internet connection problems

I hope this is the right area but if not i appologise. I am currently trying to connect my xbox 360 up to xbox live through a laptop using an ethernet cable with the laptop connecting to the internet using a wireless nerwork. I used to do it fine with my old desktop but unfortunetly that is blue screening due to a problematic hard drive. However now when i allow connection sharing with the internet connection stops working. The laptop shows a connection to my wireless box but the internet does not load up in a way allowing me to use it. Does anybody know why this is and what the problem may be.

Thanks for the answers, i cant plug the cable straight into the router as my 360 is 2 far from my router and i would have problems getting a long enough cable. How would i get the connection to bridge rather than ICSchay2005