HELP My Xbox 360 Slim wont boot or show anything on screen...

update: it also shuts down its self after 10 mins or so :'(

final update: so i guess i fixed it somehow i did the RT + Y thingy when i was on the AV mode and then i cleaned the HDMI port and now it works!!!

update 3 : is this an april fools joke or something? with the standar cables the console works just fine O_O

ok you guys, i dont have a built in wifi (xbox 360 S) or anything like that. I just have the xbox 360 slim 250gb hard drive and no other equipment. Im on the other side of the wall from my router/modem. I put the WEP(64key) password for my network in correctly.
I dont know what uPnP thing is. When im testing my wifi connection, it wont go passed the xbox 360 picture at the bootom of the screen when your testing ur connection. it just shows a big red X over the xbox 360 picture at the bottom of the screen. I dont
know what im doing wrong or anything like that.

The power supply is different because it is more energy efficient, as I mentioned at the end of my post. It will not boot faster or do anything faster though. All models run exactly the same, MS just figured out how to make them do the same thing but with
less energy required with each release. If one is running faster for you then it's likely due to the amount of stuff on your hard drive. Clear both hard drives, update them both to the latest system software, and they will run the same. Hell, my fat 360 used
to boot up quicker than my slim. I also have a lot more stuff saved on my slim's hard drive. My slim model downstairs has practically nothing saved on the hard drive and it boots up much quicker too. I don't know why you seem to think I have any desire to
lie to you, but if you don't believe me a simple Google search of "difference between xbox and xbox slim" will show you it's not going to run the dashboard, games, Netflix, or anything else faster.