I responded to your previous post about this issue. Did you try it?
For those interested, here's the link:
Windows 7 forum: Win 7 desktops icons (similar to win 3 boxes for files)
Since it's easier to follow suggestions and possible failures of those suggestions by keeping all responses in one location, I'll lock this thread so all responses can continue in the original location.
Hope this helps.
As soon as i installed SP1 my desktop icons developed a box over all of them. I have seen this before but never lasted 3 weeks like this.