enter the APM configuration (as suggested in my last post) menu under the power menu page of your BIOS. Check there for RTC options.
Don't be afraid to acctually enter the bios and look for things - just don't change anything unless you understand it (RTC Alarm is safe enough). If you think you've changed something accidentally, just exit without saving by pressing escape and try again..
Sometimes they don't write everything up in the manuals.