Worms spreads by creating a copy of itself and starts by autorun.inf files. It is essential to remove the malicious and autorun.inf files not only from computers but also from the source, and that is the USB Drive.
Some malware can modify Windows settings to disable or prevent users to change setting of Show Hidden Files and Folders under folder options. These steps will help you regain access or modify and save the settings.
Downloader.Agent or trojan downloaders may be hard to remove because it creates autorun files that will run the malware when a volume is mounted or download a copy o the same trojan from a remote location.
If in case Windows Task Manager was disabled, these steps will enable it back: