BlackBerry Curve 8300

Periodically, while browsing the web, watching a movie, on google maps, or just completly randomly, the phone just turns off and reboots. It doesn't happen all that often. Maybe like 2-3 times a week.

Is this normal? my friend has one and it doesn't happen to him, he also doesn't have all the media i have put on my mediacard.

I put 2 movies each about 300mb, some music, and some pictures. One day the blackberry wouldn't even read the card. I tried taking it in and out, rebooting a few times. nothing. Put the card in my cardreader for the computer, and it wouldn't show up. SOOO I reformatted it to the blackberry and put all the stuff back on, but hopefully it doesn't do that agian when i have more stuff on that I can't back up.

help me please again, and again