Depends how old the piano is. When you look in the lid can you see the hammers. Has the piano been kept in a damp place - maybe it'll settle down once it's been in your house for a few months.
They are extremely intricate and sensitive to the environment they are kept in. Dead keys can be nothing more than swelling of the felt bushes/wood but they need to be adjusted very carefully and are very intricate to adjust although it looks easy to do it isn't. If it's alarmingly out of tune that doesn't sound great - pardon the pun because if it's old it may have loose pins which depending on the make would mean an uneconomical repair as it would require restringing and pinning.
Also what did you pay for it? What make is it and what kind of style is it? Really I would suggest you get back onto the sellers as it has to fit for purpose" as trading standards would say which it doesn't sound like it is.
Just a few suggestions but I need more information and I would definitaely get back to the sellers (assuming it's a shop you bought it from)
Eric
April 2009
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