Ever since installing Windows 7 RC, I have not been able to run Pidgin. It would put an icon in the tray, then disappear. Finally after searching the net high and low and found this comment on an open pidgin ticket that seemed to resolve the problem.

I have XAMPP installed and the PHP subdirectory is in the path. I renamed the aspell-15.dll in this directory and the crash went away. Renaming the file back caused the crash. Seems to be a conflict between these two files.

I also had the same issue with XAMPP installed. Thanks Chowarmaan, whoever you are!