Icons are missing from Control Panel, or you cannot start Control Panel, the
Welcome Center, or games in Windows Vista: http://support.microsoft.com/kb/936686
There is a link in the article for a Hotfix that resolves this problem.
Click the link for the Hotfix, write down the KB article number for the
hotfix and then go to the following website to order the file. The hotfix is
free and they will send it usually within about 8 hours.