Verify that images are digitally signed and dump version information with this simple command-line utility.
Usage: sigcheck [-i][-e][[-s]|[-v]][-q][-u] [-c catalog file] <file or directory>
One way to use the tool is to check for unsigned files in your \Windows\System32 directories with this command:
sigcheck -u -e c:\windows\system32
You should investigate the purpose of any files that are not signed.