No. Photoshop Elements are standalone programs and you can use all versions on one PC (but not simultaneously).
Like Orlando pointed it out, you can use multiple versions of PSE on the same machine. So there is no need to uninstall the earlier version in order to use the newer one.
With regards to their simultaneous usage, Organizers of different versions can be operated upon simultaneously, while Editors of different version can be operated one at a time.
Hopefully this clears your doubt.
Thank you, I did't know that Organizers can run simultaneously (don't use Organizer, I use Lightroom).
Will it be possible to run different versions of Editor simultaneously?
There are some bugs in PSE15 and it would be very usefull to use PSE14 and PSE15 at the same time...
Like I mentioned earlier, only one Editor version can be used at a time. To use another one, you need to quit the present one first. If you are facing any issue with any of the features, you can mention it here. We will try our best to resolve your queries.
Yes, I know...I just ment if it will be possible in future to run 2 editors at a time (if it is possible to run 2 organizers, why nor 2 editors too)...
There are some issues with PSE15 and I already contacted support weeks ago, but I'm afraid that these issues will not be fixed anytime soon...