Those who create Portable Document Format (PDF) files often embed a link into the document that will open a webpage for you, or send you to a different part of the PDF file itself. Usually you can open a link in a PDF file in Adobe Acrobat Reader by just moving your cursor over it and clicking your mouse. Sometimes, due to compatibility issues, obsolescence, and so forth, this isn't the case.
Open the PDF file in Adobe Acrobat Reader.
Choose the "Select" tool. This is the button in the toolbar with an arrow on it. In version 9.0 and later, you'll find this in the Tools drop-down menu. Click "Tools,"\ then click "Select & Zoom," and then click "Select Tool." Your pointer will turn into an arrow. (Alternatively, right-click your mouse and click "Select Tool.")
Position your pointer over the link in the PDF document until the pointer turns into a pointing hand.
Click the link with your mouse. The reader will then open the linked site in the last web browser window that you opened--or move to the part of the PDF file to which the link points if it is an intradocument link. If these instructions don't work for you, go to the next step.
Download the latest Adobe Acrobat Reader. This should overcome any obsolescence and compatibility problems. To do so, go to the webpage linked in the Resources section below. Make sure you select the correct version for your operating system. Install it after the download is complete. Open it and open the document you've been working on. Click on the link again to test if it opens. If the link is still not opening for you, go to the next step.
Copy the link address and see if someone else can open it. If not, then the problem may be further upstream instead of in your own computer.