Hi Ralph, could you try this specific procedure one time, it's important to follow the steps:
Plug the 3.5mm jack of the white programming cable into the PS3 controller, don't plug the other end into your computer's USB port yet.
Poke a small paperclip into the small hole in the back of the controller to reset it.
If the controlle turns itself on, power it off (must start with controller powered off, and unplugged from the charging cable, all LED's are off, not blinking).
Hold down the mod switch.
Hold the PSHome button to power up the controller (still holding the mod switch)
Once the four LED's stop blinking and Player 1 LED lights solid, you can release the mod switch.
Ok now try plugging the USB end of the white programming cable into the PC.
Does it connect?
If it still doesn't want to connect to your PC, it might be time for the shop staff to crack open your controller and have a look at the insides :-(