It would probably be best to start a new post. On your host machine, try to ping github.com. Are you able to ping? If you are able to ping, then you can check your dns servers by executing a ipconfig /all within the windows command prompt. It should provide the DNS servers your machine uses. Then you can log into the sandbox and verify if your dns matches with what's on your host machine, nslookup command should display this. If I recall correctly, the bridged network interface setup should pick up the same dns servers as your host machine. By default that interface should be dhcp.
Hope that helps.