You may be able to delete the folder in [b]Safe Mode[/b] or you may have to go to a Non Windows system to delete the folder depending on exactly what is on it.
You can do this the cheats way and grab a Live Linux boot from that and then try to remove the Flash Drives contents in Linux if you don't want to load up a different computer with another OS.
You can find copies of most of the Live Linuxes on CD that come as Cover Disc's on many computer Mags or you could download one from here
http://tinyurl.com/23nmq
Where you can either chose to download and burn or buy depending on what you needs are. If you are looking for a Windows Repair Tool Knoppix will fit your needs best.
Col