I have just uninstalled an expired trial version of CS4 (I still have CS3). I noticed that NEFs no longer have their thumbnail when viewing a Windows folder (I have XP), but the generic unknown file type icon. So, I reassociated NEF files to be opened with CS3, and get the NEF icon now, but still no thumbnails. I tried the advice given in this thread: Just do this: Open any folder. In MENU click TOOLS. Click FOLDER OPTIONS. In the top of the window, click on FILE TYPES. Click NEW. In the FILE EXTENSION window, write .nef. In the same window, click ADVANCED. Click the ADVANCED FILE TYPE rollout. Scroll down to WINDOWS XPS DOKUMENT THUMBNAIL HAR... and click it. Click OK. Click OK again. You are done! I guess this works for many other image file types too. Good luck! but I can find no WINDOWS XP *** listed at all. My thumbails are still fine on my laptop, and I tried to see what might be associated with .NEF in the Advanced list of File types, as explained above, so I can reset it, but I can't see any way to find out, only to create a new file type. I don't think I ever had to download Nikon codecs to view thumbnails originally. Help gratefully appreciated!