Hi there I had the same problem wit the Targus. first make sure you have only one Targus Keyboard in the program list, I had put by accident 3 two with the new downloaded drivers and one with the mini cd disk. You might have to do a (God Forgive for swearing)...A Hard reset because it just wont go with the software removal program. Then download the new driver:
http://www.targus.com/us/Downloads/IRKeybd_v1_33.exe and install it. Once I removed the extra keyboard icons it did work fine....BTW to use it in landscape, place it with the top to the right and move the IR transmitter at an angle, note where the little tiny IR port is its kinda off center. Good Luck!