According to the information you have provide, it seems that you have the Intel® Wireless-N 7265 which is not dual band. That is the reason you can't find any 5GHz network even if your router/modem has this technology. Intel has two versions of this adapter, in the links below you can find the product brief of each one of these mentioned adapters.
Thks for your reply, aleki_intel. I imagine I have Wireless-N 7265 without dual band, but I am not 100% sure. Mountain say it's my fault, problem drivers... Is there any way to be 100% sure what my model is?
Yes, there is. Go to control Panel >> Device Manager >> Network Adapter. Expand this option and you should be able to see the name of your adapter or consult with your computer manufacturer for further details. Check your computer brand and access this link to find the contact information if your computer manufacturer: Computer Manufacturer Support Web Sites