As Jim indicates, there should be no problem with simply connecting your laptop and router together via an Ethernet cable. (I've never encountered any laptop where someone has gone to the trouble of disabling its ethernet port!).
Have you tried turning your router off, waiting a minute or two and then powering it up again. It's amazing how often that can solve wifi problems!
If that doesn't help though, try resetting the TCP/IP stack on your laptop. (It's a lot easier than it sounds! Tell us which version of Windows you're using if you need instructions).