(redirected) Alienware X51 MOBO swap help!!

I recently swapped out the motherboard on my x51(mobo died and I am out of warranty. I found one on ebay and swapped the motherboard out). I am trying to reinstall windows and I am having difficulty. It wont let me install the operating system or repartition the hdd .I am able to enter the bios.I am also able to start windows setup but hit snag with the preexisting partitions. Any help would be greatly appreciated. Thanks