Kim wrote:

I'm wondering if I could have been causing problems with too many USB-connected devices.

Although most external drives and similar devices are self-powered and do not draw power through the USB port, the take-away points from the laptop tech is: 1) All external powered devices are not always well-behaved by either brand or for a particular device over time. They can have voltage variations in the data lines even if they are self-powered. 2) USB port power devices normally include circuits to prevent over drawing power through the USB port power line. Again, what you get depends on the manufacturer and the device. 3) External powered mini-hubs often have both power line surge protection and data line surge protection. Read you mini-hub packages carefully so you are sure what you are buying both power line and data line surge protection. - Kurt