Bluecharm the processor may making a difference. If you are looking at some of the Intel® Celeron® and Intel Pentium® from the 3rd generation they should work without Bios update. Also understand that the Bios update for the 3rd generation Intel Core® processors was released in Jan. of 2012 so unless you have been using the board for the past year there is a good change that would have the updated bios on it.
The last thing that I do advise people on this is that if they need it over buying a processor simply take it down a local shop that may have a 2nd generation Intel Core processor on hand. If you have problems find one here is a tool we put together to help you find them.
http://inteltechpros.com/