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#11
About the key: I have quite a lot experience installing different language versions of Windows Vista and now even with Seven. I have never managed to use a key from a different language version i.e. IMO the keys are language dependent.
Just last week a Finnish Seven Ultimate clean install didn't accept a legal key for the German Seven Ultimate.
Sorry to say but I think OP's only possibility is to buy a key to an English version and upgrade with that because the Dutch version can not be used to upgrade an English Vista.
Kari