Hiya Katrina! I might have accidentally made some progress on this one yesterday.
Every time I've seen it reported and I've tried to do some work on it, it has only affected one user account on the PC.
So ... it might be related to a damaged icon cache for the affected user account. (There's one of those for each different user account on the PC. This is what I accidentally learned yesterday while trying to research a fix for a slightly different problem.)
If that's what is going on, rebuilding the icon cache might get folks past it:
http://www.winhelponline.com/blog/how-to-rebuild-the-icon-cache-in-windows-vista /
... Trouble is that that's all educated(?) guesswork/speculation, and the procedure looks a bit hairy. It's the sort of thing where I'd definitely be setting a System Restore Point for the system prior to giving it a go.