I almost got crazy but got out of it this time. Every time I wanted to view a picture, ACDSee opened twice. IrfanvView worked fine, but it’s designed oddly and unpleasant to use. I installed Image Eye, which I didn’t know of and is quite good, but it got worse: it opened, then a Windows error message informed me that the system hadn’t been able to launch the picture a second time (?!). Just in case, I uninstalled everything but Image Eye, and that was the end of all that is holy: the Windows Fax and Picture Viewer came back to life and opened every time, not responding to any kind of manipulation supposed to kill it, including the one I had blogged two months ago.
As a consequence, I’ll give you the complete trick, which I found after three Google result pages, that finally works: after you have executed regsvr32 /u shimgvw.dll as I said, you have to open regedit, search for shimgvw.dll and delete every key that calls to it. The instructions page also recommends to delete the shimgvw.dll file, but my Windows wouldn’t let me (maybe just because it’s just a Home version?).
Now I’m clean, and I’m ACDSee-free. Feels good.