SQL Server 2008/2012 Reporting Services service doesn't start after the installation

The error message you are getting when you try to start SSRS:

"The request failed or the service did not respond in a timely fashion."

Modify the registry to increase the default time-out value for the service control manager. To increase this value to 60 seconds, follow these steps:
       1. Click Start, click Run, type regedit,and then click OK.
       2. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control.

       3.  In the right pane, locate the ServicesPipeTimeout entry.


            Note If the ServicesPipeTimeout entry does not exist, you must créate it. To do this, follow these steps:

1. On the Edit menu, point to New, and then click DWORD Value.
2. Type ServicesPipeTimeout, and then press ENTER.
3. Right-click ServicesPipeTimeout, and then click Modify.
4. Click Decimal, type 180000, and then click OK.
   This value represents the time in milliseconds befor

            Restart the computer for the changes to take effect.
 Check that SSRS service can be started now...

http://blogs.msdn.com/b/mariae/archive/2012/11/12/reporting-services-service-doesn-t-start-after-the-installation-of-ms12-070-security-patch.aspx