Mouse/USB problem

I'm hoping somebody might be able to help me issolate this problem so I know what it is I actually need to replace.

I have a keyboard that connects to my computer through a USB port. In turn the keyboard has 2 USB ports in which I had my mouse and a photo card reader connected. I have had an intermittant problem for the last couple of months with the card reader suddening appearing to be not there to operating system. Some times it would just be momentary, other times I have to disconnect it from the keyboard port and reconnect it for the system to recognize it. Then just a few days ago, my mouse started locking up. Same symptoms and fix. So I connected both the mouse and the card reader directly to USB ports on the back of the computer console and everything was hunky dorey for a couple of days. Now the same problems are back and I even had one instance last night with my keyboard not working and had to reboot to fix that. The problem with the optical/USB mouse has become so persistant that I have gone back to using my old 2 button PS2 mouse (ugh). At this point I don't know if I need to:

a) replace my mouse
b) replace my card reader
c) replace my keyboard
d) replace all of the USB ports in the back of the computer console
e) all of the above
f) none of the above