New build, strange first boot problems

Just bought a radeon 4870 and an ASUS P5Q (P45) Mobo to upgrade from a 7950gt and an ASUS P5NSLI (nforce 570i). I set up everything witht the new card and mobo and when i powered on, i got no beep and no video, but everything spinning. Along with that, when i tried to power off by press and hold, i got nothing, and had to switch off by the power supply. There were also occasions where the gpu fan was quite loud. Tried using the 7950gt and no change. Then i tried using the old board with the 4870 and i was good, everything working. So i'm guessing something is wrong with my new board, or there is something i'm doing wrong with it. I was also wondering if it could be my power supply. Its an MSI turbostream 460W, and according to one partiular review, its not a very good power supply. I'm looking to replace it, but i cant just yet. The power supply is working well with the old board and 4870 though, for now. So, just asking what could be the possible problems... faulty mobo, poor psu, maybe something i need to know about this specific board. These are my spces:

ASUS P5Q / ASUS P5NSLI
4870 / 7950gt
2GB DDR2 667MHz ram
e6400
MSI turbostream 460W psu

Thanks.

Case speaker and power buttons are connected properly, currently using the ram on my old board, and it is fully compatible with the new board.

I agree with you on replacing the psu, unfortunately, i wouln't be getting a replacement until december (OCZ GameXStream 600W).

What I don't really understand is why the system wouldn't shut down when i press and hold, given that the connectors are correctly placed, i'm guessing it is something to do with the power supply, which btw is currently working with the old board.

I'm guessing either that or faulty mobo.

Case switch is currently working with the old mobo. Thing is, everything is working with the old mobo. So all i can assume is that the shutdown problem is due to the psu not working properly with the new mobo, or just a faulty mobo, though i doubt that.