I have the Vista Ultimate with SP1, so here is a copy of that file from system in a ZIP file if you wish to replace yours with a clean copy of it.
You will need to save the ZIP file and extract the
shgina.dll file to your desktop first. Afterwards, you can Copy and Replace the
shgina.dll file to it's default location at
C:\Windows\System 32.
shgina.zip < Click to Download
Hope this helps,
Shawn