06-18-2012 06:38 AM
Try to boot you device in Safe mode & check.
To boot your device in Safe mode: Pull out battery and press escape key once red LED blows, till you see blackberry bootup line on handheld.
06-18-2012 06:46 AM
Most of the time few Apps installed in device create issues, which makes device restart again and again.
When we starts device in Safe mode, then 3rd party apps doesn't start automatically and helps us way to segregate the issue is in Software or 3rd party Apps.
If issue remains same in Safe mode as well, then will suggest you to reload Software again.