If you cannot start the service because you get an error "Error 1075: The dependency service does not exist or has been marked for deletion"
What you need to do is to check if the service name is correct, like for me the service name is different because of the version of SQL I have installed. I´m using SQL Express 2008 R2 so the service name is not the same as regular SQL server.
Copy the Service name and goto the registry and browse to this key "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\AppVirtServer" and paste the recently copied service name text to the "DependOnService". Restart the machine.
If you do not have this key you can create it by right click on AppVirtServer->New->Multi-String Value and enter the name "DependOnService" and enter correct sql service name.