I've been using PP for a long time with no problems. However, I've been using a single project (and multiple sequences within it). I recently tried making a new project with different settings - upon watching the video exported from this, it freezes (In Quicktime, VLC and even when uploaded to video sites such as Youtube and Vimeo).
So, this was a disappointment after I'd worked on a project for a while - I tried making new projects, even with the same settings as my single project that does work, and found the exact same - the video exported freezes a few seconds in.
Is this a problem many have come across? I have an issue in that I have no way of re-accessing registration details - this account was simply made for a trial download. If there are any solutions that do not involve reinstallation, I'd love to hear them.
Other than that, I think you'd need to provide more information about the media used, the system used and what you're trying to accomplish.