Here is a quick single command line method for adding a Skype contact to your list. First hit the Windows key and the letter R to open up the run dialog box. Next type the following with no spaces and hit enter.
Obviously change skypename to the contact of your choice. At that point an edit field opens up and asks you to say hello to who ever it is you wish to add. If you already know the person's contact name you wish to add this is the easiest way to do it.