ALERTS no longer working

Calendar alerts have simply stopped working . . . I've missed several important meetings

I need to replace or fix ASAP . . . I got hooked on iCal alerts, now can't live without them.

I noticed the Mountain Lion version changed significantly.

I set an alarm just like I always did . . . sometimes multiple alarms to keep reminding me.

When I update, and close the event . . . then open again, all the alerts are GONE.

I put in a single alert. It's there, but doesn't go off. I miss my appointment.

Version 6.0 (1639)

MacBook Pro

15-inch, Mid 2012

Processor 2.6 GHz Intel Core i7

Memory 8 GB 1600 MHz DDR3

Graphics NVIDIA GeForce GT 650M 1024 MB

Software OS X 10.8 (12A269)