I recently upgraded my computer and in the process decided to upgrade Premiere Elements as well. I had been using 3.0. I was happy to find that pre 9 opened my 3.0 .prel files just fine, except for one caveat (so far...). If I attempt to render the work area, the progress window pops open then imediatly shuts, and begins playing the unrendered work area. I can render the entire project if I go to 'Share'. I can also render a work area if I open a new project in 9 and add similar files. Any idea what to try next. I still need to edit the video, and using the old computer isn't really an option (working on this video was part of the reason for upgrading the computer). I thought I could be clever and somehow copy paste the contents of one project to another new project created in 9.0, but you can't have two projects open at the same time (at least no obvious way). I could install 3.0, but I really would rather not, I don't even know if side-by-side installs are supported.
In my books, I recommend never opening an old version project with a new version of the program. It almost always leads to buggy behavior -- especially when it's a jump all the way from version 3 to version 9.
I'd very much recommend you finish your version 3 project in version 3 and start a new version 9 project in version 9.
Otherwise, there's usually no fixing the problems that occur.