Turn on Terminal Services and configure it to accept connections

Make sure that your server has all the necessary updates through microsoft/windows update.

Then on the server, do the following:
Click on Start - Settings - Control Panel
Select Add/Remove Programs
Click Add/Remove Windows Components on the left hand menu
Find Terminal Services in the list, click on details
Select Enable Terminal Services
Click OK
Click on next and when asked, select remote administration mode
Reboot the server

After this point you should be able to use remote desktop to connect to the server.