I have used Picasa for a long time, but recently a serious recurring problem has appeared. I run Vista 64 bit. Last week a pop up appeared stating that Picasa was upgrading. When it finished, the desktop was blank save for the recycle bin and picasa icons, all the programs had gone from the start menu, and all my personal files had gone. I was able to recover by using system restore and from my back-ups. When I went into Picasa the same thing happened. When I eventually recovered again, I uninstalled Picasa, and downloaded it afresh from the website. Again, the same thing happened. This time I am not using Picasa, but I wonder if anyone else has experienced this problem, or know what is causing it?