Your best program would be Microsoft Office Publisher. When you start that up choose the size of business card you want and design away. You can also choose one of the provided templates to get you started. By the sounds of things you don't have Microsoft Office Publisher and so your going to need to buy it. Instead you can download a free, open-source program called Open Office. it's very similar to Microsoft Office and is also very compatible with Microsoft Office. You can download Open Office here: http://www.openoffice.org/ I'm not very experienced with open office so you might need to Google a couple of things yourself.
Good luck.
