I got nasty problem with USB Flash Drives (mass storage). The stick works perfectly with other computers. Other USB 1.X devices works perfectly(mouse and keyboard). USB WLAN stick also have issues, so that it breaks up the connection from time to time. I have tried several different drivers with USB WLAN and it makes no difference. But the main problem is this: When I plug the usb flash drive, it recognizes it (Kingston Data Traveller 2.0) and I can even read data from it, even very fast. But the problem start when I try to put some new stuff in it. Ex. I want to copy a big video clip to it, when I drop something to it, it starts to do some "calculations" for few seconds, then it popup message showing the the file is already there and aks questions should it be replaced. When I answer "replace", it gives me copy error "0x80070570". Afterwards I check the flash drive, it shows the file there but the size is 0kb. Also, it usually disconnects(!) the flash drive automatically after a while. The problem does not exist when I'm turning USB 2.0 to disabled in BIOS or if I use 2GB <= flash drives, but that's not a option for me. I just got new 500W Nexus power supply, some I'm a bit doubtful if there is any power issues. My MB: ASRock > Products > M3A770DE I'm very open to suggestions. What could the problem? Has anyone else having same kind of problem? If you do, can you post list of your computer parts so we could pinpoint the problem.