Removed windows vista and installed windows xp pro on my acer laptop now program

I dropped my acer 3680 laptop and operating system went away. Lack of funds i was given a windows xp pro install dick for a dell cmp. I installed it and it does kind of work but now for instance facebook pages are bigger then screen tried zoom functions can not seem to get it right. Also now no sound, orl wi/fi connection. had to install a netgear adapter to get on line,and now asking for a product key tht i do not have. can you help please? The screen issue most importent. thank you.