How to Check if your Laptop's built-in or External Wireless Card have 5GHz Network Band Capability

Bought a new laptop or a new external wireless card for your computer and it can't detect your WiFi connection. The main problem is that you have an internet connection on your all devices except that new laptop or computer with the new external wireless card. 
First of all, you need to check 5GHz network band capability.

For Windows users

Open up command prompt(cmd) on your computer and execute next command:

netsh wlan show drivers

Now if you see the 802.11a or 802.11n in "Radio types supported" list, then your wireless card is compatible with 5GHz network band.

For MAC OS X users

Open up the Spotlight and search for "network utility". Open up "Network Utility" app from results.
Now go to "Info" tab and from drop down menu select your WiFi network interface.
if you see the 802.11a or 802.11n in "Model" line, then your wireless card is compatible with 5GHz network band.

For Linux users

Open up terminal and execute next command:

sudo lshw -C Network

And look at "wireless=IEEE 802.11***" line. If you see 802.11a or 802.11n, then your wireless card is compatible with 5GHz network band.