If you try to find and install a display driver for HP Proliant Microserver N40L you will be disappointed.
The display card is not detected and HP doesn't have a display driver for it.
The card is "ATI Mobility Radeon HD 4200 Series".
The driver can be found on AMD's website.
For your convenience, I've extracted from the downloaded package only the driver.
This is for Windows 2008 r2 and Windows 2012 & 2012 r2 (also for W7 and W8 64bit).
You can download the driver here.
If you download the driver from AMD, the Catalyst Software gives an error and does not install.