Is there anyway one can toggle a light using a program on a computer?
In general, you can do it, but you will always require some extra hardware. I'm going to assume that when you talk about lighting "an LED" you do not mean a mains-operated LED lightbulb, but rather a small LED which you can buy separately.

In this case, what you should do is go on eBay and search for "USB relay". Get the cheapest you can find and you will be able to drive it from your PC's USB port. You'll need to connect the relay contacts to the LED, a current-limiting resistor, and some sort of voltage source (which can be a 9 volt battery if you don't mind the limited battery life).

If you are trying to light an LED lightbulb, you'll need to do two things. Second, you'll need a relay board which is rated for 120 or 220 volts, depending on where you live. First, though, you need to STOP WHAT YOU ARE DOING AND FIND SOMEBODY WHO IS AN ELECTRICIAN SO YOU DON'T KILL YOURSELF. And I mean that sincerely.