DeleteRegKey: doesn't work as expected
 

As written in http://nsis.sourceforge.net/Add_unin...emove_Programs
I added

WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\ImageMaker" \
"DisplayName" "Image Maker -- super software from Great Northern"
WriteRegStr HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\ImageMaker" \
"UninstallString" "$INSTDIR\uninstall.exe"

so that the application appears in the Software wizard of windows. This works. But when I deinstall, this entry doesn't vanish. SO I added

DeleteRegKey HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\ImageMaker"

but with this additional command, the application DOESN't APPEAR in the Software Add/Remove dialog anymore! Is this a bug in the latest 2.41 version?

Well, if you delete it, it has no reason to appear there. What you should do is delete the key in the uninstaller and not in the installer.