NIS 2011 Idle problems

Hi, I recently purchased Norton Internet Security 2011 on the Norton site. Saying I’d get 2012 for free.

 

I installed it, left my computer idle for about an hour. I come back and see a dos screen up with the message ‘Reboot and select proper boot device or insert boot media in selected boot device and press a key’

So I turned the pc off and turned it back on. Windows loaded fine, but Norton would not load at all. I tried the FAQ nothing worked, so I used the Norton Removal Tool. I then reinstalled Norton Internet Security 2011.

It then had a different layout.

 

I still get the ‘Reboot and select proper boot device or insert boot media in selected boot device and press a key’ message if I leave the computer idle for an hour, but Norton still loads, so that problem is fixed.

 

Do you know how I can fix this being idle for more than an hour problem? Even if I Log off, Lock the pc. I still get the error if the pc is on.

 

I was using a free AVG anti-virus before this, if that could be the problem?

 

Thanks