bought a fujitsu siemens SCALEO P mce pc from pc world with xp mce2005 installed....after getting a backdoor trojan that i was unable to remove i decided to reinstall mce 2005,didnt get a media disk with it just a lot of other crappy software,so after contacting pcworld they told me that i would have to contact fujitsu who in turn wanted 60 quid from me for a setup cd no way i thought after forking out a fortune for the pc so i borrowed a 11in1 disk with mce 2005 on it when it asks me to enter my key from my coa sticker on side of case setup tells me its an invalid key can anyone tell me why this is happening,coa sticker on case is definately media center 2005