Well, the fix is in and it doesn't involve Don King or the Supreme Court this time!
You may (or may not) remember that on the 21st of May, I blogged about a problem I was seeing on multiple systems. The problem was that for some reason, these systems were no longer able to open or print multiple files from within Windows Explorer.
Anyhow, I have found the fix! It was actually added to my comments last night.
Thanks so much to povilas for providing the fix.
Open up registry editor (regedit.exe). Go to key HKEY_CLASSES_ROOT\*\shellex\ContextMenuHandlers. Export the key using File menu->Export...
Delete all values in key HKEY_CLASSES_ROOT\*\shellex\ContextMenuHandlers except for Open With, WinZip and WinRAR (those are the only ones that I could keep in the key and still open multiple files, but your mileage may vary.
You might also have to delete the following keys in order to get it to work, however, I was able to fix the problem with just deleting stuff in the key I mentioned above.
HKEY CLASSES ROOT\AllFilesystemObjects\shellex\ContextMenuHandlers
HKEY CLASSES ROOT\Directory\shellex\ContextMenuHandlers
HKEY CLASSES ROOT\Drive\shellex\ContextMenuHandlers
HKEY CLASSES ROOT\Folder\shellex\ContextMenuHandlers