Which operating system are you using? Premiere Elements 10 is a pretty old version of the program and may not work on El Capitan. Also, if you've got a Retina screen, that two could negatively impact this program's performance.
Also, it appears you're trying to edit MP4 files, which version 10 does not edit well. Remember that, back when version 10 was released, most people were still editing tape-based video and AVCHD was just getting support.
I'd recommend you download the free trial of Premiere Elements 14 and give it a test drive with this footage -- just to see if that alone resolves your problems.
Hey Steve! So I think I'm running Mavericks but yes I do have the Retina screen. That also makes sense that version 10 would not edit those HD MP4 file well.
I went ahead and tried out Premiere Elements 14. Not only was that problem fixed but everything ran much smoother overall!
Another thing I want to mention in case other people are having this problem. When I was using version 10, my buddy would send me MP4 files but the audio and video would not match up in the editor although it would be in sync elsewhere. In version 14, I had no out of sync problems.
Thanks so much Steve!
Great news, lludawg!