Do you have any Anti Virus programs installed and running currently? I know there was a post a few days ago with people having random explorer.exe issues/crashes, and BSODs, and disabling their Anti Virus program helped. --DKnight
I don't know if using unreleased updates is going to help.... I had this issue for a while with my desktop but I figured it was due to my roaming profile and folder redirection. The only thing that fixed it for me was blowing out all my profile and recreating it. Even then it was still hit and miss at times, eventually after a clean format it sorted itself out.
isolate any applications or dll's which load via appinit, it may be a dll thats incompatible with windows 7 explorer.exe