Keeps beeping after Hard Reset

[kmh2011]

I did a hard reset on my phone (press & hold silver button while turning on) to clear my data but ever since then it's been beeping very loudly and obnoxiously every so often and I can't get it to stop. It's not a message indicator of any sort, nor is it any kind of beep I recognize (aka not one from the list) and I don't believe it's signalling when voice privacy is unavailable because it kept beeping even when I turned that signal off. Anyone have any idea?
P.S. This is a Verizon phone with Windows Mobile.

[rudeboy]

could it be something in the alerts (Start > Settings > Phone Settings > Alerts)