problem opening files from windows explorer

one of the users in our shop is trying to open a part fromwindowsexplorer and when he does he gets the error "Windowscannotfind .SLDPRT.  Make sure you typed thenamecorrectly, and then try again.  To search for a file,clickthe Start button, and then click Search"  

he says it will eventually open if he keeps trying it, butit'sstill kind of annoying.  it will open fine if heopenssolidworks first, but i would think that the fileassociationsshould be good enough to know to open solidworks whenyou click ona solidworks file.SolidworksAdministration