Adobe Acrobat Reader cannot view PDF in an internet browser

I am having issues with the Adobe Acrobat Reader installed on my computer. It has an error saying that I have to close the application if it is currently being used. None of the suggestions posted on the different forums online actually work.
I always get this error when viewing a PDF file on any internet browser such as Internet Explorer 8 or Firefox. The same PDF file can be viewed without any problems using another computer's browser. I can also download and view the PDF file locally on the computer. I am stuck. Can somebody share their knowledge on this issue?
Thank you.
