hmm? did you put SDR and DDR modules together?
if not.. theres something wrong with the motherboard itself... how often does it gives a good POST? ayaw lang sa boot sa windows.... if you can boot good then i recomment you to try MEMTEST 86+ -
http://www.memtest.org - and have your rams inspected for errors.
in my experience there are some boards that undergone changing of mem types kay magpa reinstall sa windows para maka adjust ang windows sa iyang bag-ong environment... but to some other boards... okay ra man no need to reinstall.