I am trying to move my websites from shared hosting to the vps I rented, so I am trying to set up LAMP stack. After installing all, the server works fine at start, when I visit it's IP address on browser, I get the apache2 test page. But, after some time the page stops working (error message saying that the IP address didn't send any data), and after a while the test page appears again, but this time it shows apache+centOS landing page (instead of ubuntu one). At the point when the page stops working, the server loses the ability to ping anything or communicate with ubuntu archives.
I've tried to reboot server and services multiple times, went through a clean install again and the same thing happens. After the server reboots, everything works fine for some time, so I tried to update everything, but that doesn't help as well.
My vps is on hosthatch.com, it runs Ubuntu 14.04 x64, it has 3x Intel E5 3.5GHz+ Core, 2GB RAM, 40GB SSD, 3TB Bandwidth.
I need to move my websites from the hosting to the vps soon, but since the website are live, I can't put them on the server that is misbehaving.
Does anyone have any ideas on how I can solve this?