3GS: white screen when some incoming call and sms

Hi friends, my iPhone 3GS (os 3.1.2) screen white, when some incoming call and some sms, not all the time, some time.
Each day I've facing 3 to 4 times and when screen white,
I can't pick a call or can't see sms even can't press Home button also screen dead.

I can only do as press Top Button once then can press menu button.

any solution or any hardware or screen faulty?

my iPhone using screen protector, is case that problem?

any advice will be helpful and thanks in advance.

Helpppppppppppppppp

My google search for your problem shows a number of similar problems with just as many " solutions " if it were me I would restore as a new phone from a fresh download of 3.1.2 if that doesn't resolve your problem it's time to find an apple store.

Hope this helps
Clay