Ok here is the scenario. Say you have an AA battery running to a switch then to an LED then back to the battery. Simple stuff. What I want to do is replace the switch with a computer. Run from a power source into a parallel (or serial) port, then back out to a device (LED) so when the user clicks a button on the screen, the corresponding LED turns on.

Dose anyone have any experience with this type of thing? ANY help at all would be appreciated.

DemonMade