Before you start tinkering with global.asa files, let me caution you about the file's execution process. Giving a global.asa file a new timestamp and datestamp (e.g., by saving the file) causes the file to execute—even if you don't make any changes. When you save an application's global.asa file, your IIS server will finish processing any current application requests before it recompiles the global.asa file. During that time, the server will refuse any additional requests and return an error message to any users trying to access the Web site.
After the server has processed all the current user requests, it will delete all active sessions by calling each one's Session_OnEnd event, closing the application, and calling the Application_OnEnd event. The server then recompiles the global.asa file. The first user request after the recompilation will trigger the Application_OnStart and Session_OnStart events to start the application and create a new session, respectively.