New user, 2nd hand machine.

1) I have been gifted a beautiful little AAO and I am a really happy bunny but when I try to send an email from the email app it keeps putting in the previous owners name and although I have set up another account with my own name it still keeps inserting the previous owner's name. What do I need to do to fix this?
2) The machine I have was bought in Portugal so the keyboard is Portuguese and so is most of the system. Although I have added English to the languages I cant seen to find how to toggle between English and Portuguese.
3) Why do I get sound when I play Youtube videos and not when I use the BBC iPlayer?
4) the previous owner trashed the Documents folder so that when I click on 'my documents' nothing happens. Do I just need to create a new Documents folder titled 'Documents' or is there more to it than that?
5) has anyone succesfully managed to run MacOSX on theirs? If I want to try should I 'max' the ram first or do I need to replace the SSD with a hard drive? I would have thought the SSD would run faster?

many thanks

Mac user, 20" iMac, 15" Powerbook G4, 13" iBook, Palm Tungsten T5.

 

Try to run console and type:

Code:

oobe

This should set-up default system w/o any "previousownerstuff"...