I upgraded my T-Mobile 8320 to software version 4.5 about a month ago. Everything worked fine at the time of the upgrade and for a few weeks after. About a week ago, the alarm stopped working. It would still show the alarm menu on acreen at the time the alarm would supposed to have gone off ("Dismiss, Snooze for 5 Minutes") but there was no sound. I was late for work twice before I started using a different alarm clock, however, I really depend on the alarm function on the phone. Anybody have any ideas? I wasn't messing around with settings that I can remember, or done anything that might have triggered it. The speakerphone still works ok, so I assume that it's not a hardware issue.

Have you attempted changing the alarm tune? Look in your Profiles > Advanced Settings and edit your Active profile > Alarm.

Change the the tune used for the alert and see what happens. Perhaps in your upgrade process the tune in use became corrupted or deleted?