I have a Dell 4600M laptop I have used for years at work. I recently retired and was able to keep the old laptop after the company wiped it clean and reloaded the original Windows 7 operating system. Since I got it back the Wifi connects but sometimes thinks there is no access to the internet. I trying to solve the problem I discovered Both of the Intel boards listed as hardware and drivers for both are loaded. I used the Intel site and updated both drivers and the problem seems to be gone. It appears that the Intel ProSet/Wireless WIFI is used to connect while the Intel ProSet/WiMax is Off. What is the difference and does it matter which is being used to connect?
After looking at this, I wonder if what you have is only a single solution, namely the Intel Centrino Advanced-N + WiMAX 6250. In this case, it doesn't matter; what you have is a dual-band solution that can deliver 300Mb performance when using dual band 802.11n connections. Enabling the WiMAX capabilities usually requires a separate utility. See here for more information: https://www.intel.com/content/www/us/en/support/articles/000005572/network-and-i-o/wireless-networki....
Note that there are significant benefits to upgrading this capability with later-generation WiFi solutions. Whether you can do so is dependent upon whether Dell's BIOS will support this upgrade (they often use White Lists or Black Lists to limit what can be used in an upgrade). You need to ask Dell what specifically can or cannot be supported.