Even worse playback issues after rendering

I am new to the Adobe Premiere Elements video editing software (Premiere Elements 15). I had been experiencing minor playback issues with my project, and had been receiving the "for playback errors, render your timeline" message. After researching what exactly it meant to render your timeline and having a brief understanding of it, I decided to render the entire project that I had made so far. Now I am experiencing major playback issues with my project. Keep in mind that I am new to the software, and realize that I may have done something wrong, but I would like to know if I can fix these playback issues. Can anyone help?