When you first started using it I'm assuming you only had 8.5.1 on your computer at the time? If it has been doing this since back then how have you been able to develop code? Regardless, if it has been giving you problems since you first started and you have uninstalled and reinstalled and it still didn't work then the problem might be because of the performance of your computer. What OS do you have? How much disk space is left? What are the specs of your computer?
One other option I can think of is to try just uninstalling 2009 (do not reinstall it) to check if you're still having the numerous crashes/slow downs. Other then that I would try updating your current programs to all run on one version (make back up files just in case) and just use a single version (whichever one you are most familiar with).
