The only light on the PC is the power light and the HDD light, the power LED isn't too bright, the same for the LCD monitor and the HDD led is in the back of the PC case, the keyboard leds can be easily turned off so it isn't an issue. Now the real problem comes with the optical mice included in the PC. My older mouse will get bored of being red-shiny all time and will turn off but this new mouse won't, it keeps shining bright red light all over the desktop all night long.
Something has to be done...
The goals to this instructables are:
Kill the red light.
Keep the mouse aestetics nice and unscratched, since it's brand new and good looking.
Same or better functionality.
No analogic/mechanical electronics involved (forget about putting a switch or anything like that).
Well, the goal was achieved very easily and with a very few tools.
I'll show you on the next step.