HTC Inspire doing "abnormal reset."

A few months ago, I got notification on phone that it did an "abnormal reset" and asked if I wanted to send report to HTC.  I followed instructions and did so.  The phone was in my bag when it happened.  Not in use or dropped or anything like that.

It happened a few more times over the next few months.  Between yesterday and today, it has happened THREE times.

What is causing this and what should I do about it.  From what I have read since yesterday, a number of people think it is caused by the gingerbread update to 4.3.3.  That is the version I am running.  But I have absolutely no idea what gingerbread is.

An help is appreciated.

Thanks for your reply.  Phone is less than 1 year old.  Shouldn't be battery, but you never know.

I will stop by AT&T when I get a chance and see what they say. 

Phone continued to do abnormal resets daily.  Saturday afternoon, I went to ATT store.  They advised me to try HTC Sync and see if that worked.  If not, call HTC Tech Support.
HTC Sync wouldn't even recognize phone.  Finally got phone recognized, but said "no memory card installed."

I called HTC Tech.  They advised factory reset.  We did that.  Saturday evening, reset again.
Another one overnight.  Continued reseting during Sunday.  Many times.  Reset apparently made problem worse.  I called Tech Support back.  They switched me to Repair & Warranty.

I have to send phone for repair.  It is still under warranty.  Told me to back up using Sync.
Again, Sync said no card in device.  I was told to remove battery, cover, SIM and card before shipping.  So I guess I will have to take my chances.  Most of my stuff is on card and all contacts are on SIM. 

will report repair results when phone comes back.

I tried the Sync yesterday and everything was okay.  But to be sure, I backed up SD in a separate folder by mounting phone as disc drive and copying files.

I'm shipping phone today.  Will report back with results. 

I would think that they might have suggested bad SD card, but you never know.