I just thought I'd upload some more pictures of how my LEGO PC was built. This time emphasizing the power and keyboard buttons...
The power-on button is made entirely of LEGO Technic pieces. The cables are fastened by squeezing them between the parts.
The dimensions of the PC are: 27,5cm wide, 33,5cm deep, 23,4cmtall.
The dimensions of the keyboard are: 29,5cm wide, 16,1cm deep, 4,8cm tall.