new motherboard stange problem.

This is my first try at changing a mother board and iam getting a strange error. my system is a Intell core 2 e 6600@2.40ghz with 4 gdites of coursair xms ram, bfg 8800 gts with 640 mb of ram all the hard drives and opticals go through sata.
I have bought a bio star tpower i45 mother board. on fitting the board it posts and propts to either enter bios or carry on with the default settings after checking the settings where correct I saved and exit. The computer restarts and then after a couple of seconds the cpu fan spools up to full speed the slows slightly no graphics or windows. So i clear the bios and start again but this time i carry on with the defalut settings. the computer starts up and is useable .upon trying a restart though same again. again buy resteting the bios it works normaly any help? please before i crack.:cry:cry