For instance, on my 80GB eMachine, I have from time to time had to do restores that take my PC back in time and sometimes complete destructive restores that take my computer back to it's original factory state or capabilities. The original factory settings and abilities on this older PC leave something to be desired however and usually take a couple of hours of updates to get it back up to speed. Whether you have restored your older computer or have recently purchased a used or older computer, you might have to remove, then update or reinstall some of the newer versions of certain applications.
My computer was sticking and freezing utilizing Adobe Reader on PDF files. The solution was to uninstall the Adobe Reader 6 that was on my computer by going to Start - control panel- Add/remove programs and removing that older version of adobe reader. Then I simply went to the adobe reader website and uploaded the adobe reader 10.1.0 which works for my PC. If you have a mac you will need and use different versions and methods. After uploading the newer version of adobe reader, I found the file in my documents and clicked on that document to download it and install it. After that my computer never froze again while reading PDF files.