Try calling tech support. Since you cannot install the game you will not be able to register it so tech support will probably ask you for the product key, unless he / she states you need to register the game first.
Your Windows Registry may be slightly corrupted so you may need to do a fresh install.
In the unlikely case you were sold the wrong language / region version of the The Sims 2 (I assume), then you need to contact the seller and get an exchange or refund.