Xbox 360 Slim won't power on, whatsoever. Help maybe?

Long story short. My power supply fried a week ago (Or what I thought to be my power supply frying.) In the middle of playing Saints Row, my system powered off, and there was a red light on the power button, and when I tried to turn it back on, it come back on for a split second and then just shut back off, and I wasn't getting any error message on the screen, it was just a black, and completely blank screen. I initially thought it was the system, but when I went onto Microsoft's trouble-shooting site, and I tried everything they suggested to no avail, they said that my power supply was fried and I would need to order a new one. So, I had a sigh of relief realizing that I wasn't going to have to buy a whole new console.

So, I ordered a new PSU, plug it into my system, and not only is my system not working, it's not getting ANY power, at all. No beep sound, no light, NOTHING. This is a brand new power supply, so I'm sure it's not that. So, I've looked online to find what causes this issue, and I read somewhere that it happens due to bent/damaged USB ports and in turn won't let the console power up. So, I checked my USB ports thouroughly, and made sure all of them were in place, not bent, and not damaged. None of them were.

I also plugged in my brand new wired controller, and tried powering the system up by hitting the center Xbox home button on the controller, to an astounding no avail. So, I'm really in a bad spot right now, and have no idea where to turn to fix my system. And, I'd really rather not have to resort to getting a replacement, because I really don't have the money. Does ANYBODY, have any clue as to what else would be causing this, and could I fix it, or has anyone else had this precise issue, and if so did you fix it and how were you able to fix it? Thanks, guys. I'd really appreciate the help if you could afford to help me.

Unplug everything...the wall connection, to the PSU, Xbox, etc. It comes apart in several places. Once plugged all back in make sure light on PSU is yellow or green.

how are your usb ports ,

if one is broken and the metal prongs are touching the top or bottom , your 360 will not turn on for saftey reasons, if its not that then your system is fried period

Thanks for your input fellas. Yea, I tried to look into all the USB ports with a flashlight and all of the plastic center pieces were indeed in place, and the copper pins weren't and/or toucing the metal casing. So, I have no idea. I don't know if there's a short somewhere inside the system or the power supply input. Something is seriously wrong. And, I take GOOD care of my things, especially my consoles. Due to me being a heavy gamer, and given the fact I had one of original 360's RROD on me, I've always been extremely cautious, maybe even to the point of sheer paranoia. So, I know it's not something I've done in the midst of being careless. I have no clue. Anyone else maybe have any other ideas possibly? Thanks again, guys. If I can't fix it I'm definitely getting one this wednesday to get paid if I absolutely have to, because I REALLY have been looking forward to Borderlands 2, and I preordered it as well.