Are you sure you installed both? They should be easy to identify: Start > All programs then navigate to Corel Paintshop Pro X8 and there you will see one with the mention of (64 bits) and the other has no mention. That is, obviously the 32 bits.
If you don’t see both, maybe you didn’t install both. That is a common mistake for someone who has a 64 bits machine to think they need to install only the 64 bits version.