|""Save one port which when connected causes whole system to freeze...."|
Take a close look at that port with good lighting.
The contacts in it may be bent such that they're touching something they shouldn't..
If so, remove the AC power to the computer, if it's on a laptop remove it's battery, and try un-bending them.
Another possibility is some desktop mboards -e.g. Asus - have headers for two USB ports or a firewire port that have identical pin arrangements - 9 pins on a double row - . If the problem port is a case port or a port in a plate on the back of the case in a slot space, it may be connected to a firewire header, not a USB header. If so. having anything plugged into that mis-wired port will cause serious problems and the mboard circuits will be damaged if whatever is plugged in too long..