This submission ["View" button in Slide Show Gadget doesn't work] has been removed because
Third-party software issue
Clicking the "View" button on the Slide Show gadget doesn't open the picture.
I found the problem: it was the context menu extension "FastFolders" (by www.desksoft.com), a utility which I can not live without, by the way! I contacted DeskSoft and they already fixed the problem in the latest version.
This also fixed my problem, that the Office 2007 shortcuts in the start menu didn't work. Now everything works fine again, including FastFolders.