HTC India — Problem related to virus in my phone... Frequently auto shutdown and all..

Address:

Nagpur, Maharashtra

I have htc desire 816g dual sim phone... Bt from some days it becomes problamatic to me... Due to virus problem... It is frequently auto shutdown... Any app get downloaded and installed... Some icons like calling may disappear for sometime... Ur service provider said do system update for removal of virus i have done that also... Bt it is not working... So can u plz tell me what should i do...