Some more ideas:
1. Have you tried manually setting the laptop's gateway and DNS server to the router's IP address?
2. In the Connection Properties, have you tried disabling IPv6, rebooting, and using IPv4? (This should work if your router assigns IPv4 addresses, as practically all consumer-grade routers do; but could cause problems if you directly connect the laptop to the Internet.)
3. Have you checked to make sure that the service "DHCP Client" is set to Automatic and is running?
4. Have you tried disabling User Account Control? (This is for diagnostic purposes, not as a permanent fix.)
5. Have you tried disabling autotuning:
netsh interface tcp set global autotuninglevel=disabled
6. Have you tried uninstalling and reinstalling the network adaptor? (Make sure you have a copy of the driver saved somewhere in case you need it.)
-Rich