Hi I try to re-install window vista home premium for my laptop using the COA key under the laptop and it say the key is not valid during the installation. I'd try the window vista home premium key from "Vista OEM SLP keys" sticky thread and it went through so I know that I have the correct window vista version. I tested my COA key under the laptop with the "online PIDCheck" and the key was good. Product Key : Validity : Valid Product ID : Activation ID : Edition Type : HomePremium Description : Windows Vista Home Premium - OEM:COA Edition ID : Key Type : OEM:COA Crypto ID : Any one have any idea? any suggestion?