Have you encountered the following PHP error (or something similar) before in your Windows Vista?
Warning: session_start() [function.session-start]: open(C:\Users\YOURNAME\AppData\Local\Temp\php\session\sess_ficdel21e6lupsojqdk62ofts5, O_RDWR) failed: No such file or directory (2) in C:\webapp\folder\index.php on line 24
The solution to the above error is really simple. Simply re-create the folder
C:\Users\YOURNAME\AppData\Local\Temp\php\session\. For some reason, you or your Windows Vista (e.g. during a disk cleanup) may deleted all the files and folder under
C:\Users\YOURNAME\AppData\Local\Temp\ and this is the main reason PHP can’t find the correct location to create its temporary file for new session.