I want to change one of the default icons of Vista

Not sure this is the right place, BUT can't find anything better so I try here first.
I want to change one of the default icons of Vista. As far as I know Windows uses two: a blank-ish default icon and one for files that are not quite unknown but don't have an icon. This sounds like acacadabra (but magic doesn't work) - maybe it's a lot clearly if I mention which icon I mean: it's the first (nr. 0) icon in SHELL32.DLL. I'd like very much to change this icon, without tinkering with the shell32.dll-file itself. Can't find the spot in the registry (if any...) to do this. Have been searching for an answer for ages, without any luck. Can anyone help?

Sorry, but any resources in a system DLL file require the modification of that DLL to change them. You have to use a program like ResHacker to do it. It's not for the faint of heart, as you are doing something that if botched can really screw up your system.

Thanks for your fast answer. I was wondering whether this icons could be changed via the register, because two default icons from Shell32.dll - Unknown and * (the 1st entry in HKRt) can be changed there. Also I was wondering what the 'name' of this 'filetype' is -obviously not Unknown or default. This icon is only shown for exe-files that don't have am embedded icon (like old DOS-programs) - but if you change the default EXE icon in the registry you loose the specific embedded one. Hm, is this clear enough..?

What you can do is store icon files (*.ICO) separately on your computer and then reference those to change the icon you want for your shortcuts. That's about the best you can do at this point, as far as I'm aware.

The registry just points to information and stores configurations. It does not actually store pictures or other data. Also I agree that you should mess with dll files because doing so can result in stability issues.