In ASP.NET 1.0 you have the option to maintain the session state on an external process, in SQL Server, by setting the mode attribute of the sessionState tag in web.config to SQLServer. The problem is that the data is stored in the SQL Server’s Temp database, and thus the data is lost if the SQL Server machine is rebooted. In ASP.NET 1.1 you can use a persistent database instead of Temp, and thus make the session state survive a reboot. To create the session tables in a new ASPState database, execute the InstallPersistSqlState.sql script that you find under the :systemrootMicrosoft.NETFrameworkversion directory, instead of the InstallSqlState.sql you run under ASP.NET 1.0 (this script is still available, if you don’t need persistent session state).

If you haven’t upgrade to .NET Framework 1.1 yet, you can have persistent sessions anyway, by download the InstallPersistSqlState.sql and UninstallPersistSqlState.sql scripts from this MS KB article.