Below is copied from an amazon review. http://www.amazon.com/Replacement-PS-Ke ... B0009RKLMG
"OK, folks, listen up. There are two kinds of USB - PS/2 adapters. There's this kind, which simply changes one plug for another. It doesn't do any signal processing at all - it's just a dumb plug changer. For most of you, this will not work, because in order to use a PS/2 keyboard with a USB plug in the back of your computer, your adapter needs to change the signal somewhat. That's why you see the more expensive adapters - about $12 to $15. Those have circuitry inside them that actually changes the PS/2 output of your keyboard into a signal that the USB input of your computer will recognize. I learned this the hard way, too."
USB->PS2 adapter didn't work.