Hello georgedone and welcome to the forum.
There are two possibilities I can think of to explain what is going on :
[li]Your system’s USB drivers are messed up (TheDiggler : this might help you as well)
[/li]- See here : http://www.aeonity.com/trialerror/usb-driver-pains-part-ii-20060810-1642
[li]The USB ports on your system are dying (less likely)
[/li][li]Your USB devices are all failing one by one (highly unlikely)