Samsung tablet sm-t310 play store, internet self-open, are redirected to unwanted apps

[chuckz22]

As soon as my tablet wakes up and connects to the network Internet and play store open by itself and are redirected to an app, such as a photo-app etc. Suppose I open my tablet and start reading a book, then it is being interrupted this way. I could not find a solution on the Web and just let it go for a while.
Recently apps started downloading by themselves. I keep finding .apk in my download folder.
What to do?
I installed Avast, but it just scans installed and updating apps, no malware has been reported.

 

[bluzman]

Go to the Play Store and open the menu in upper left corner. Select Settings > Auto-update apps and select "Do not auto-update apps".

Also go to your device's Settings menu. Select Security and make sure that the "Unknown sources" box is not checked. WARNING: If you want to download an app from a site other than the Play Store (say the free app of the day from Amazon), you'll have to check this box so that the download is allowed.

Hope this helps.