Nice to know of that oddity. The file [user32.dll] should be resident in at least three locations, all identical.. and at least a year or more of age. If a very recent date (just a few days), then a Trojan or virus may have 'molested' it!
So far, my AVG has not posted the file with a warning.
The file is on the OS install disk [i386].. in compressed format. The OS install would extract and configure it, with the install date.
F@H.. to solve mankind's maladies.. in our lifetimes!