I purchased a new usb 3.0 hard drive and a pci usb 3.0 card and installed them to my computer for use as a backup in windows 7 ultimate 64bit. The drive is recognized and it works fine until I proceed with a backup operation. After a few hundred megabytes of files copied it suddenly says that destination is not available and the procedure is halted. I have gone through the usual steps of reinstallation of drivers and such, but I have the same problem whenever I am copying a significant amount of data. In order to get the drive back as recognized it requires a reboot. My system is a ASUS M4a78T-E board with 8g of ram, pci express radeon 5700 graphc and multiple sata drives and burners. Please help me. I am frustrated.