When the core library does not work anymore, Acrobat / Reader can no longer run because the components it depends on do not load.
> Enable the hidden Admin Account on Windows 7 ( Ref : http://www.howtogeek.com/howto/windows-vista/enable-the-hidden-adminis trator-account-on-windows-vista/ )
> Disable all Non-Microsoft Startup Services. (Ref : http://helpx.adobe.com/x-productkb/global/disable-startup-items-servic es-windows.html )
> Disable all the Antivirus softwares temporarily from the computer.
This error is known for conflicting Antivirus softwares like CA, Norton,Mc Afee etc.
> Delete the all the contents in the locations mentioned in the doc :
Note: It's possible that your system doesn't contain all of the files and folders listed in this document. If you do not find a listed file or folder on your system, proceed to the next file or folder on the list.
> Reboot the computer and install Adobe Reader 11 and check
As dozens of other similar topics in this forum indicate, the error may be the result of a rootkit infection.
Google for "scan for rootkits" and check your computer for such an infection.