ARTECK HB192 - Help Please

I've had the keyboard for almost two years now and I like it. It's pretty affordable and connects to 3 devices, however, I pressed some buttons earlier and I lost the number pad function. The numbers operate as directions in Excel files. There is no NumLock button so I've played with all the buttons and still can't find the combination. I've also reset the connection and see if there is an updated driver, none worked. I've googled and another model keep showing up with the NumberLock button which is so frustrating, hence I am here...on my last whim asking for help.