Mcafee update, windows could not upgrade system files before starting

Okay, I recently installed a new version of McAfee.  I went to update the dat files, everything went fine, then it says to restart.  Did that.  When I restart the computer it tells me this:

Windows could not upgrade the file %1 from %2

%1: %2

 (it says this 7 times)

then

Windows could not upgrade one or more system files before starting. Windows may not start or run properly.

If Windows fails to start run setup again.

Press any key ton continue...

(so i press a key, then it says---)

Completed updating files, continuing to load windows.

So when I get into Windows everything seems fine and everything.  But the update is not applied to McAfee.  Why is this happening? What do I need to do???

Thanks,

Courtney