Windows error

Hi, I'm new to SW and juse the SW 2008.
I run it on windows XP SP2.
When I click on a Sw file, windows says:"can't find the file, control or you've written the namecorrectly and try it again. When you will search an item go toStart and Search"
I click always ok than double click again the file and it opens inSW! But why is he always saying for the first time can't find?
I'm already behind it that when you go to the file-info and youde-select archive, the file will open directly.
So my question are there more people with this problem??
How can I solve it, are there settings in SW to set the ARCHIVEoff, or must I save the file in a other format (it is now.SLDPRT)??
Or do a re-instal?
Thanx, ThomSolidworksGeneral