When we use Windows 7/vista/xp it doesn't give us full bandwidth speed as it has to maintain OS IDLE MODE. This idle mode is also applicable for processor, RAM, Audio & Video processing units to comfort a user but using or applying some tricks we can do it very simply.
By connecting flash drives to the affected computer, often it shows flash drive containing just some folder's shortcuts. Sometimes it shows nothing though drive's properties show it has files in it. Even we get some inaccessible folder or file. This type of problem may also seen in our local drives (HDD partitions). Even paid anti-virus is unable to resolve those folders, they just scan and detect The AUTORUN worm which one will execute all programs. Then our important files remain hidden.