Building NEW RIG NEED HELP!!!

Hey guys so any help would be appreciated. So I have a PC I bought back in late 2006 (upgraded to nvidia 8800 GT later, already had amd dual core x2, 2gb ram etc.). I would save a lot of money just replacing the motherboard with a new intel mobo, adding in a core i7, along with a nice amd 6950/70 or GTX 570/80 perhaps. I've done the price comparison and I seem to come to about 500 to 600 bucks total (Mobo, processor, and video card). The case looks practically new, has major ventilation, and I believe the power supply is 750 watt. My question is will I have any problems connecting the power supply to the new mobo? Is it safe to say power supplies haven't changed much? The raid Hard Drive setup is good enough (600 gb). I also plan on just install windows 7 to the new mobo (since windows xp is what is on here now). I feel this is possible but I don't want to be wrong... Thanks.

Forgot to add my powersupply has 24 pin connector!

Thanks. Hopefully everything else connects up to the new mobo haha.