We have 3 PCs in our house - 2 on Windows 7 32 bit (notebooks) and a desktop running Windows 7 64 bit.
I had the no thumbnail preview problem on the 64 bit system solved with the 3rd party patch download. It works great now. I then noticed that we have the same problem on one of the notebooks running 32 bit. It has got me stumped.
I first noticed this when running Reader X, so down graded back to Reader 9. I noted that with Reader X I could not get a preview of the PDF contents in the preview pane (when activated), nevermind not get a thumbnail preview (miniature depiction of the of the files contents rather than PDF icon). When I downgraded to Reader 9, I can get the preview pane to work, but still no thumbnail preview, although preview thumbnails for other file types e.g. JPEGs are working fine. Thumnails are turned on.
Anyone got any ideas on this, or is it just one of those things to have to put up with?