I have a Dell Dimension 3000. It's been slow these last few days, even displaying the low virtual memory warning. I ran Microsoft Security Essentials on it, I didn't do a full system scan, but scanned some of my recent downloaded files few days ago. I needed to use my external hard drive. The USB cable was already plugged in, so I plugged in the power cable to the hard drive. Then, BOOM! Everything except the fan in the computer stops working. Even the Ethernet port doesn't light up. How is this even possible?