Help Samsung Galaxy S3 Problem

[Bani99]

hey
i have bought a SGS3 recently and one day i connected to my computer and since that day it started slowing down.Sometimes the screen froze and apps kept sending errors and closed unexpectly.
Now my phone restarted itself
Can anyone help??
thanks in advance
Android Version 4.1.2
Not modified
Firstly i thought it was a virus problem so i installed a couple anti-viruses ''Dr.Web,AVG,Avast,Kasper-Sky" but they didnt find any virus.Now i have only Dr.Web
The apps that i have installed when this problem started were some games:"WildBlood,Need for Speed Most Wanted,Backstab HD,Brother in Arms 2 etc

 

[ExtremeNerd]

Moved to the S3 forums since this seems a very specific problem. Can you post more details? What software version? Modified? What apps have you recently installed?

This certainly isn't normal and something you've done recently could explain the problem.