What would be a good default username for a PC resetup.?

I work at a tech company and usually they put "Preferred Customer" as the default username for a Fresh resetup pc to sell to someone. I'm trying to think of a better shorter name to use as the default. I've thought of "User", "Admin", "Owner" "Dell,HP......(Name of PC manufacturer)". I don't really feel like these are professional or would make any sense to the buyer. Anyone got any better names?