Can states change how the Electoral College works?

My state just changed the way the electoral vote is decided so that it coincides with the popular vote.  Is this constitutionally legal? This defeats the purpose of the Electoral College and does an end run around the founding fathers wisdom that an election should not be decided by only the popular vote.  If this happens, all the states which are more populous will end up deciding who gets elected.  As an independent voter, this disturbs me because it will keep one party in control of all elections and this is wrong.  Please tell me if there is a way to fight this?