gamecube video game system on a lcd computer screen? The computer monitor has a normal computer input.

Assuming you have a computer hooked up to the LCD monitor, I've done this before by using a video-capture or TV Tuner card through the computer.You can get a PCI TV Tuner card which allows for standard video inputs (usually coax and composite), these tend to run around $50 or less. Once the hardware and software are installed, simply hook the gamecube up to the Tuner card as though it were a TV, and the software will let you view the console output on your computer monitor.Basically, turn your computer into a TV and everything falls into place for hooking standard TV accessories to it.