K/UbuntuOS/ZorinOS 64

[GeraldCC]

Hi To all,
I have been trying K/Ubuntu and Zorin on 3 machines and the software seems to 
turn off the usb ports after a while--anywhere from 30sec to 30 mins.
These system run IDE+SATA1+SATA2 combination.
On a 4th machine, some 6YO a 64FX53, using only IDE drives this does not 
happen.
All these systems feed through a Belkin usb hub to supply wireless keyboard 
and mouse.
Your thoughts on this subject will be greatfully received.
Gerald