Wont Let Me Create PassWord

i recently bought a compaq presario (1 gig(put 3 more in) dual core x2
4200 ) and it refuses to let me make a password i disable UAC still
nothin Cut Off My AV still nothin it refuses to let me make a password
another thing is that seeing as how i bought it from best buy everything
says best buy instead of my acount name like if im playin a game or
download a document or installing something it says C:/Best buy it might
just have to contact best buy about that but any suggestion for the
password thinks guys.....


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Rseniss