Just to make sure, have you checked to make sure that the PSU is actually switched to the on position? Same with the surge protector/power strip if you use one.

lol, yes. fortunately, I'm not blonde

With my old case, all the connectors like "Reset Switch, Power Switch, Pow LED, ect." were all in one connector, so it was impossible to mess up with that. In the new case, most of the connectors were separated, and its not very clear if I should plug the "Power Switch" facing which direction. Theres a blue cord, and white cord, both going into the plastic part labeled "Power Switch". My dad's case was like this too, but it works fine. I really hope I didnt screw up the motherboard by accidentally getting that wrong.

Is there a way to power it on, without using the Power button? If I could do that, and it powers up, then I assume it would be the motherboard? and if it didnt power up, it'd probably be the PSU..? Assuming theres a way to do this

If the headers are within easy reach, you can take the head of a screwdriver and touch it to the two pins that connect the power button instead of using the power button. Unless your motherboard has a built-in on/off button, that is the only other way I am aware of.

Assuming I'm doing this right, it didnt work. I put a flat-head screwdriver across the Power pins, and there was absolutely no reaction. Though, if I did short out the motherboard by putting the Power Switch in the wrong way, then I assume this wouldnt work anyways.

I could try to use my dad's power supply, but is there any possibility that if the motherboard has shorted or something, that it could damage his power supply?

I just read that if the power supply is making a high-pitched sound, that its probably bad. Since I got my power supply (i would guess 3 months ago) its made a high pitch sound when I unplug it. If I plug it in, and turned it on, it was fine. But if I unplugged the power cord from the back, it would make a high-pitched noise for around 10 seconds. Not everybody can hear this high pitch though. I just thought it was me.

I got my RAM today and installed my new motherboard. My god is this thing impressive. I was expecting, maybe, a 20% gain and I ended up tripling my performance in BF3. From ~25 FPS on minimum settings to ~50 on medium. I got the overclock on the i5 holding steady at 4.8GHz. Skyrim on ultra, steady 60 FPS, ~45 near a LOT of water. Crysis 2 - ~45-50 FPS on 'Extreme'. This is all on a GTS 250 GPU, mind you. This thing is amazing.