I got home last night from a 4-day vacation. I attempted to use my Inspiron 17 various times during our stay, but the wi-fi was virtually non-existent at the hotels and so it would not connect, or would have very slow service.
Today, I tried to connect to my home wi-fi, and was unable to use the internet because the connection was 'limited'. I tried scanning for viruses, restarting the computer, rebooting, but nothing has worked. I did do some troubleshooting, and have the ethernet cable connected now which is the only thing that works. My mom's laptop and my iPhone connect to the internet just fine and have no problems.
FN +F2 is the suggested step to enable WIFI on your system. If the WIFI is enabled and the system is not detecting any networks available near to your system i would suggest you please revert to us with the snapshot of the device manager by expanding options under network adapter along with the version of Operating system installed.