If you right click on the instance and click start, it takes longer than usually and give an error message
which says “The sql server failed or the service did not respond in a timely fashion. Constul the event log or other applicable error logs for details”.
You can see the error be going to to this location
C:Program FilesMicrosoft SQL ServerMSSQLMSSQLLOG
If you have multiple instances replace MYSQL in the above line by MYSQL.1 or MYSQL.2 etc
To fix this problem go to Control Panel > Add Remove Software > SQL Server 2008 R2
This will ask you for the installation copy of the file you downloaded or you have it on disk. Note: .exe (which is the installation) will not work. You have to uncompress it to a folder.
After this, it will present you with a dialog to select which instance you want to repair. Select the troubled one. And let it reinstall everything. It will most likely fix the restart problem as it did for me.