Razr v3m calendar reminder won't stop ringing

I have a red Razr v3m with Sprint service. I use the Calendar
reminders quite a bit, but more often than not I experience a strange
problem.

As soon as the reminder is set off, there is nothing I can do to get
the phone to stop ringing. The screen is simply frozen (showing the
wrong time), and no key I press makes it stop. If I wait for about a
minute or so, it finally stops ringing and the text of the reminder
finally pops up. Most of the time I just remove the battery because I
can't deal with it.

I have another phone line with a gray Razr v3m, also through Sprint,
and have no problems with that one. I've already upgraded to the
latest firmware. Is there anyone else out there experiencing this
problem?

Thanks,
S.