WiFi driver not working

Hi!

I have my Dell Inspiron 15-3521 and I just bought a new HDD for it last Tuesday. I installed Windows 7 on it today and when I was installing the driver for wifi/bluetooth (from Dell's website), it says "Setup has detected an incompatible version of windows." (first screenshot) I have Windows 7 Ultimate installed.

I also noticed that in Device Manager lists, Network Controller is not installed! (second screenshot) Again, I tried downloading it from Dell's website but to no good. I have my ethernet driver working properly but I need my wireless connection. I also installed drivers in order that's why I don't know what to do now.