Hi, I assembled a new PC for our Movie and Video Editing Team. The configuration is : Motherboard ASUS P9X79 Pro Model Processor Intel Core i7 3930K Sandy Bridge-E 3.2GHz RAM Corsair Vengeance 8x4 GB kit , 32GB total RAM Boot Drive Crucial m4 256GB SSD Video Storage WD Caviar Green 3 TB Desktop Internal Hard Drive (WD30EZRX) Case Cooler Master USP100 Power Supply Cooler Master 750W CPU Cooler COOLER MASTER Hyper Blu-ray Burner Asus CD/DVD/Blu-Ray Burner OS Windows 8 Pro 64Bit GPU Nvidia 4GB GeForce GTX 670 Monitor 24 inch Samsung Monitor LED Everything works perfect, but there is a serious problem. If I connect any pen drive or external hard drive to any of the front or back USB ports, the computer hangs. It doesn't hang at the first instance. As soon as I start to copy or paste something , it starts with a good speed and them goes all the way down to 0 bytes/second and the PC freezes. Then if I take the USB drive, the PC gets back to normal immediately. All those USBs which I tried have been used in a Apple iMac before . But I tried 2 brand new pen drives and external hard drive and it works perfect and copies nicely as well. But the USB devices which hangs, I even tried formatting it on windows, mac, and everything , but whatever we do, it just doesn't work and hangs. What can be the possible reason ? Is there a way to debug this ? Do I need to ask for Motherboard replacement ? For example, I just took of the pen drive Sandisk 16GB Cruzer , formatted it on another windows computer , then connected it to this PC. Like always, the windows 8 growl said, there is problem with a drive, click to fix. I clicked it and ran for 1 min and then said, it cannot fix it. I clicked on event details when that error came and I attached the screenshot here. And just then , the PC hangs when I tried opening it from My Computer. And when this happens, the drive on My Computer always changes its disk space view to a blank FAT 32 sort of view. You can see that on my attach screenshot. And yes, this only happens with any USB storage device and not keyboard or mouse or speaker USB. Just the old pen drives or external drives. And even if I format, they dont work. Of course, there is no kind of virus thing, since Windows 8 is loaded with Windows Defender. So, let me know, how to deal with this now ? I have put on a lot of money on this and this problem is driving me crazy already.