I had this issue when I first started working on the server, always going to pause and such.
The logs showed little to nothing and everything was done correctly in the config files.
So the issue that fixed this for me was reinstalling MSSQL 2008 R2, the thing that I noticed before this is that in the SQL Server Configuration Manager the SQL Server (One with the little play button next to it.) Did not say MSSQLSERVER like it should. It said SQLSERVER or something along those lines. I reinstalled and it then said MSSQLSERVER in big letters and then server stayed on play.
How to do this is when going through the SQL setup, Make sure that you use the default instance that says MSSQLSERVER Like So
And then you should be all set.
I know this very well could not be the issue but it did solve the issue when I was having the same issue as you. And yes I did in-fact have this issue every time I installed it with a named instance. As to why I am unsure, but it seems MSSQLSERVER default instance works just fine.
Thanks,
Baserk.
(Hope this helps.

.)