A few months back I installed SQL Server 2008R2. At the time of installation I used

1.Mixed Authentication  

2.NT Authority\NetworkService as the SQL Agent user name, and the same user name for all other components also.

At that time everything worked. Now when I start the Agent I am getting this below error.

> 
> Windows could not start the SQL Server Agent (MSSQLSERVER) service on Local Computer.
>  Error 1053: The service did not respond to the start or control request in a timely fashion.
> 
> 
> 

I followed this link (<http://support.microsoft.com/kb/322140>). The steps are not clear to me but I tried a few. When I run by using `cmd` as admin I get this error:

> 
> The program can't start because sqlncli10.dll is missing from your computer. Try reinstalling the program to fix this problem. 
> 
> 
> 

Please can anyone help me with easy steps?