Please remind me on what computer operating system is your Premiere Elements 13 running and if you have updated 13 to 13.1 yet using an opened project's Help Menu/Updates.
For troubleshooting...what specific video transitions are involved in the freezing when you apply a transition?
The first thing that I would explore are the edges of the two clips involved with the transition. Please trim a few frames from the end of the first clip and a few frames from the start of the second clip, put the clips side by side, and then place the transition. Is the problem less or gone completely or still there in full force?
Are you getting project freezing when you do anything else in the project?
Please consider and then we can decide on further troubleshooting strategy if necessary.