Nokia Lumia 520 Rebooting every 5-10 mins, what can I do?

[Windows Central Question]

Nokia Lumia 520 Rebooting every 5-10 mins

from yesterday it is rebooting every 5-10 minutes, i didn't install any updates/software's recently.today i tried resetting to factory defaults once using "last backup" & another time using "fresh copy".but still problem exists. below is the information & please help me and thanks in advance.

Phone Information

name:windows phone
model: Nokia Lumia 520
carrier: CV GBIE
Software : Windows Phone 8.1 Update
OS Version: 8.10.14219.341
Firmware revision number: 3058.50000.1425.0006
hardware revision number:1.5.0.1
radio software version: 2.0.242037.8
chip SOC version: 8227
screen resolution: 480x800

Software Information

lumia cyan
accessories agent 3.0.2.1
device client information 1.4.2.9
Feedback to Nokia 2.5.0.17
Firmware update notifier 1.0.3.4
Glance pinboards App Agent 1.2.0.0
nokia first use experience 1.8.0.0
nokia share 2.3.0.5
nokia spamfilter 1.8.0.32
silent installer 1.5.0.0
sim unlock 1.0.0.5
sms vcard receiver 1.2.1.7
manufacturer name: RM-914_eu_euro1_327
mobile operator:000-GB
configuration ID: 452357
application version: 3.7.1.16
build creation date: 18-08-2014