For about the past month or so, I have had a huge problem with my macbook pro. Whenever I plug in a USB device such as an external hardrive, a flashdrive, a digital camera to upload photos, or even my ipod, the whole screen instantly goes dark the second the device is connected. Once the screen goes dark, a message comes up saying that I need to hit the reset button or hold down the power button for several seconds. The only 2 USB devices I can still use to my knowledge without receiving this error are my iphone and my USB mouse. My software is up to date. If I plug in my external hardrive via the firewire port, it works perfectly fine. But if i use the USB port, then BAM same thing happens every time. It used to work perfectly fine up until a month or so ago. I cannot figure out what is causing this to happen. 
Somebody please help me and let me know if there is a way to fix this??
Somebody please help me and let me know if there is a way to fix this??