d3dref.dll

Can anyone help me with this error message?

The protected system file d3dref.dll was not restored to
the original, valid version, because the Windows File
Protection restoration process was cancelled by user
interaction, user name is #####. The file version of the
bad file is 5.1.225.400.

I can login and work normally but this error will pop up
and I can cancell it but it comes bad a little later
please help.