I've been reading a few articles about using different formats for the flash drive. it doesn't say how bart-pe2usb formats the drive (NTFS/DOS?) I've found that by using NTFS i get faster boot off the flash drive, but some virtual-HDs won't boot over USB unless they are formated in DOS-FAT32. You can try using DISKPART to set the FS=NTFS. "FORMAT FS=NTFS QUICK" Then you will have to also copy the windows sector boot.ini and boot.ldr to the flash drive using XP tool "Bootsect f:\windows /s F:" where F:\ is the flash drive. For detailed instructions on how to do this with win7/win8 see September issue of CHIP-Magazine Malaysia, or download their article "Windows8 On a USB Flash Drive." To see the complete CHIP article click here...http://goo.gl/CwmA1