I got 2 fairly old (I'd say around 8 years old) USB slots on the front of my PC that don't function normally lately. Most of the time, mostly when I insert a big external HDD, they are connected and disconnected from my PC for even 10 times in half a minute, in which case I remove them to prevent any damage to the HDD. I tried with some USB slots on the back, connected via a USB hub, and it was even worse, the one I connected was making clicking sounds so I got it out immediately. None of my external HDDs or flash drives have a problem, in fact they work completely normally as they should (but only half the time when they are connected to this PC) and I have almost never had problems like this in my Ubuntu OS (dual-boot on the same PC) during the same time-frame. Moreover, the external HDD that showed the most problems was a brand new one which I used about 3 times. Now I'm completely abstaining from connecting anything but flash drives on my PC which is a big nuisance. What's at fault here? Will I need to make a new purchase?