PDFs will open within your browser window by default.
Locate the Adobe Reader toolbar at the top of the article.
The toolbar will disappear when not in use, so it may be necessary to move your mouse over the top middle of the article to force it to appear.
To print the article, click on the printer icon on the far right of the Adobe Reader toolbar.
First, verify that your printer is functioning properly.
If your printer is working, try saving the PDF to your computer and print from the saved file rather than the browser.
If saving the PDF to your computer does not work, print the PDF as an image. Directions will vary depending on your printer menu. Below is a typical configuration.
Finally, reinstall Adobe Reader.