VNF3-250 Mobo problem

[igloo15]

I bought a new printer and hooked it up to one of the top usb ports but it wasn't getting recognized so I switched it to one of the bottom usb ports. Instantly my computer turns off. No idea why so I go to turn it back on but it won't turn on. I open the case and don't smell or see anything so I turn powersupply off and then on and try again but still nothing. Since today the system has been running like a dream but I have never used the bottom usb ports before so I don't know if this was an on going problem. Anyways I waited a while and kept trying but still I am unable to even get anything to turn on in the system. Here is my stuff

Thermaltake Silent Purepower W0013RU ATX 480W Power Supply
Amd 64 3000
Nvidia 6800gt
2x512mb Cosair ddr 3200 ram
2x100gb HDD from western digital
Dvd-rw drive
dvd-rom drive

Thats about it. Any help will be greatly appreciated.

 

[igloo15]

Ok I tried taking out the cmos battery and using the reset jumper. Also tried starting it barebones to see if it would post but I am still not even getting it to turn on.

 

[montag451]

Check you have switched the switch on the psu to 1 (if it has a switch on it)
Try a different plug socket
If nothing turns on, then check the fuse in the plug.
Then, see if you have a replacement power lead lieing around.
Then,
open up case
try and trip the power on connectors with a screwdriver
If still NOTHING - try a new psu

 

[igloo15]

The problem I see here is the motherboard because well this has happened before with this same board and I RMA'd it and put the new one in and it worked. The problem before was the usb too. My usb keyboard stopped working so I decided to switch the usb port and upon doing so the computer shut down and was unable to restart ever.