A Windows error occurred when I clicked on the "Download it Here" link in the "New Version Available" message box. The error message read (something like) "Windows cannot find http://www.pokertracker.com/products/PT3/download.php.
I run Mozilla Firefox as my default browser. There is a feature in Firefox that recognizes when the last browser session terminated abnormally, and asks the user if Firefox should restore the last session or start a new session. I believe that the error above was caused by this feature. I hard-booted my PC after it locked up, thus forcing Firefox to close. When I clicked on the "Download it Here" link, I got two message boxes: the Windows error above, and the Firefox message box that prompts "Restore Session" or "Start New Session." I clicked on "Start New Session," and the PT3 Download page opened normally. I then closed Firefox and PT3, launched PT3 again, and clicked "Download it Here" again. This time, the PT3 download page opened without error.