Logitech MX 3200 Cordless Keyboard and Mouse not working

Yesterday my cordless mouse indicator said that batteries were getting low.  I shut down the computer and turned off the mouse.  This morning I installed new batteries in the mouse turned the mouse back on.  Nothing happened.  So, I installed new batteries in the keyboard, too.  Nothing happened.  I re-booted the computer, nothing happened.  I unplugged the USB cordless connector and plugged it back in, nothing happened.  So, I got out the old corded keyboard and mouse, plugged them in and I can now access my computer.  I re-loaded the Logitech disk, nothing happened with the cordless connection.  I am at a loss as to what to do next.

I am using a Dell Inspiron 530S system with Vista, which I purchased from Dell in January 2009 along with the Logitech cordless system. 

Does anyone have any suggestions for what to try next?

Thanks,  Sandra