It's always sound advice to test a new piece of software before you commit, and ProShow 5.0 is no exception. But how can you test 5.0 without losing 4.5?
The answer is that you install 5.0 in a completely different location.
First, make sure that you still have your 4.5 installation file, in case you need to reinstall it in the future:
Now, before you start to install ProShow 5, create a "ProShow 5" folder on your C: drive.
Once you have that created, go back to your pspro_50 and double click on it to start the installation. When you get to this window stop:
If you continue on without changing the file path, you'll write over your 4.5 program.
Click on the Browse button to navigate to the new ProShow 5 folder you just created.
Before hitting the Next button, uncheck all of the checkboxes for the Installation Options. This will insure that the two programs don't conflict with one another.
After completing the installation, all of your launch icons should still be attached to 4.5 (that's why we unchecked the check boxes!). So you'll have to launch ProShow 5.0 directly from its Program icon in your new ProShow 5 folder. There's a lot of stuff in there, make sure you double click on the little blue (or yellow, if you're using Gold) wheel to launch ProShow 5.
That's it! You're all set to play around with ProShow 5 without losing ProShow 4.5. I don't recommend having both programs open at the same time, though, the Presenter program might get a little dizzy!