Are you using the supplied HTC cable? Sometimes other cables just don't cut it and can make your phone fubar'd. Also do you have USB debugging mode on? if so turn it off. If not, turn it on.
Most cables are universal but sometimes they proprietary. Using an older USB cable may be backward/forward compatible but using a USB 1.1 cable on a USB 2.0/3.0 device can cause glitches....not because of the cable purse' but because of the USB controller.