Try this 1
You need to install all the drivers. The yellow exclamation mark indicates that
drivers are not installed properly. You can download the drivers from the
Click on the below link and follow the instructions
Enter your "Service Tag" or Select the option "Automatically detect my Service
Tag for me " and click on "Continue"
Select the option "Choose from a list of all Dell products" --> Click on "Continue"
--> Click on "Laptops" --> Click on "Latitude" --> Click on "Latitude D520 ".
Now download all the drivers and install it.
Some devices may not function properly if the drivers are installed out of
order. For more information click on the below link.
So install the "Chipset" drivers first.