Naomi (and copying Denis on my reply)
SQL Notification Services is not a good choice - Microsoft discontinued it in SQL 2008.
From Microsoft: "Moving forward, support for key notification scenarios will be incorporated into SQL Server Reporting Services. Existing Reporting Services functionality, such as data driven subscriptions, addresses some of the notification requirements. Features to support additional notification scenarios may be expected in future releases."
If that answer doesn't help, other tools, like some combination of SQL Server Agent and SSIS packages with WMI tasks, might help. Obviously, you'll want to test anything for scalability and performance issues.