In the Google Chrome browser, when you click on a PDF file link, it will just open the PDF file in your browser. Some people might find this option quite convenient but you can only view the file. The good thing in Chrome is that you can easily disable this. Go to your Chrome browser and enter the following in your address bar.
Simply find the PDF Viewer option and click Disable. Once you have disabled the PDF Viewer, you will now be able to download PDF files normally. When you open the PDF file on your desktop it will open up in your default program. If not, then you need to disable the Adobe PDF Viewer in the Chrome plug-in page. Adobe Acrobat also adds a PDF viewer to the Chrome browser; you should also check and delete the other PDF viewers in Chrome to fully disable Chrome from opening up a PDF file.
You should also check your computers default program for PDF files and make sure it is not set to Chrome browser. On a Mac, a PDF file might open using Preview and not Adobe Acrobat. You can change this by right clicking on the PDF file and going to Get Into, then in the Open With section, pick your desired program for opening PDF files and click on Change All. This will change the settings of all the PDF files and make the program of your choice as the default PDF viewer.