Error on Plesk for Windows server: Module "IsapiCachesModule" could not be found

[senthil]

Symptoms

• On a Plesk for Windows server, instead of the login page, users will see a blank screen with the title "500 Internal
  server error".
• The following error can now be seen instead of the blank screen after the steps below are executed:
  
  • Edit C:\Program Files (x86)\Plesk\admin\htdocs\web.config and set
    errorMode="DetailedLocalOnly" then save the file.
  • Open the Plesk login page again within the server browser.
    HTTP Error 500.0 - Internal Server Error
    Module "IsapiCachesModule" could not be found
    
• An antivirus has quarantined files from the C:\Windows\System32\inetsrv folder.

Cause
DLL system files were infected from an unknown source.

Resolution
Contact Microsoft Support to obtain a genuine copy of the missing files.