Could I Install SP1 on windows xp

I have sql server 2005 standard edition.I have downloaded sp1 but can't able to install.I want's to know could i install it on windows xp.as on the page of sp1 i have read that it is for longhorn and vista.

I have the problem of creating diagram of my db.When i run

ALTER AUTHORIZATION ON DATABASE::pubs TO [kamranshahid\yukon]

it gives me the error.

Cannot find the principal 'kamranshahid\yukon', because it does not exist or you do not have permission.

I can't able to resolve it by command.I can't able to install sp1.What else can i do should I trash my sql server 2005 standard edition.

It seems you have 2 problems;

1/ Can't install SP1 of SQL Server 2005 on a copy of Std running on Win XP, correct? If so whats the error?

2/ You can't create diagrams on your RTM instance, correct? is 'kamranshahid\yukon' a user in the database? what perms does it have? what user are you logged in as an what perms do you have?