I bought a macbook off ebay and when I tried to use it,it had a password is there a way to remove the password or did I just waste my money?(seller does not refund)

Contact the seller.

If you have the original discs that the unit comes with, then you can either reset the password using the discs, or reinstall the operating system(erase and install, which is probably good, since you don't have anything on it).

Instructions for the reset are here.
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I know this is off topic but I didn't want to make a new thread,so if someone could help me,I want to know if this dvd burner is compatible with the macbook or a dell latitude D800http://www.bestbuy.com/site/olspage....=1177717727747
http://www.bestbuy.com/site/olspage....=1176506511356
could someone please tell me which one I should buy?