First deactivate the product(s) and then uninstall it from the machine using the procedure specifically for your OS. If in Windows and I suspect it is then uninstall from the Control Panel.
To deactivate the product you need to go Editor and then:
Help >> Deactivate
Please also make sure that you have your original CDs and /or DVDs handy including the necessary serial number as you will need them to install the product(s) again.
After uninstalling the products, you need to restart the machine before you start to install again.
You have created the backups of your sentimental photos, right? You need to just in case the machine causes more problems down the line.