Why won't my computer turn on with a webcam plugged in?

Question

Electronics

If a webcam is plugged into the USB port, then the computer does not try to turn on - there is no reaction at all to pressing the power button. If you pull out the camera, then the computer boots normally, if you insert the camera after loading, then it works without problems.
Equipment:

• Webcam - cheap Chinese 640x480, Kreolz
  
• 2007 ASUS P5QL Pro motherboard
  
• Power supply 400 W, came with noname case
  

What could be the reason for this strange behaviour?
UPD: the problem appeared over time, initially everything worked.

Answer 1

Contacts at the usb camera are closed.

Answer 2

Most likely the camera hangs the BIOS - you need to disable USB keyboard support in the BIOS, update the BIOS, throw out this camera and buy a normal one, if you took it in the store you can exchange it under warranty (incompatibility with the motherboard).
PS You can also plug it into usb 3.0 - it does not always work in the BIOS. (But it is unlikely to be on the 2007 motherboard)