BLU 5.0 keep restarting, no login

Couple apps were no responsive last night, so I power off and restarted, from then, the phone keep restarting, no login come up. Only show couple icons, like battery usage, time. Then couple minutes later, it tries rebooting. then black screen with couple icons on the right top corner.

I tried remove the battery, tried to drain the power, same thing.

Anyone know how to fix this other than reset to factory?

Thanks

Frank