I just bought a new soyo case for my a7n8x w/ xp 2400+ but the power supply is sideways and blocks more than half of the fan and is 1/2 inch away from the fan. It won't run any lower than 76c/168f degrees W/O any overclocking. Any suggestions?
See pic in attachment

To rule out the PSU as being the problem run the PC with the PSU half pulled out. I did that in the past for testing with my Lian-Li PC-50 case which also features a sideways mounting for the PSU.
I've never found it to be much of a problem with temperatures. If the PSU fan is running at higher speed (unlikely) then I could see if causing a problem. Check that the heatsink is mounted well and making correct contact with the core.

My sideways mounting PSU (http://www.techspot.com/gallery/showphoto.php/photo/299/password/0/sort/1/cat/500/page/1)

looks to me like it is pulling hot air from the PSU and feeding it directly to the CPU fan to cool it. That is not very efficient to say the least.

If that is the case, turn the CPU-fan around, so that it blows hot air AWAY from the CPU.

would that be very effective?. turning it around. i have never thought of it. and it looks like thats the only option. nice stuff Mr. Guinness. just my $0.02

if you have the cash, you could buy a duel-fan PSUwhere one of the fans is on the bottom of the PSU. That way you can use the PSU to lower the temp around your CPU by sucking ambient air out of the hotspot, in addition to the CPU heat sink. Oh, and tie up some of those cables for more airflow. It looks extremely crowded in there.

I have the same problem, except the PS only has 1 fan (exhaust) I have a soyo barebone with 3000xp. It was running at 59 deg c with a good cpu fan. I've got it down to 39 deg C with CPUIdle!

Amazing!

I too would turn the fan around and see if that helps.

Also, worth a look, recon you could manage to squeeze this on?
http://directron.com/badongs80.html