I bought a laptop from dell and they forgot to include windows. so when I asked them to give me windows, they sent me my copy of vista home premium and a key with it. Now, when i try to activate it, I get an error saying its an invalid key. I cant try activation by phone coz I dont have access to a phone here 
There is a week more remaining to activate it.
So please tell me how to get the activation done.
thanks in advance.
-Abhirama