Keyboard and mouse problems

I recently purchased a microsoft Wireless comfort Keyboard 1.0A Model 1027 from a office depot that was closeing a store so it was clearance demo model with the wireless mouse as well , . It came with no software but I searched and downloaded the drives , and somehow fumbled my way to getting it to work. But after 3 days of using it , I came to my pc and the mouse is working , but not the keyboard , . I've tried changing batteries and tried reinstalling the drivers , but no luck . So I had to dig out my old mouse and keys just to come here and as for help . any suggestions ?