Hi Thorsen,
already tried

no differences... as I said I am an experienced user and I tried several things before posting.
This is a kind of last resource. Of course I could reinstall Win 7 on another partition or HD and then export the FolderTypes from that OS and import on mine, but I figured I could have saved the time just asking to somebody who already has Win 7 installed.
I know I deleted only entries in FolderType and so if I can restore all those, I should be back to have everything up and running. As I said from Vista I got most of the entries back, but some are still missing and so some things still don''t work (for example the Network and Sharing Center is empty even though I can connect to the internet without problems.
Thanks again, have a good day