How to delete a hidden locked folder

Recently helping a client servicing a laptop, and my thumbdrive being infected by viruses and a folder being created, named "re". I tried many ways to delete the hidden folder but it keep on saying "Cannot delete file: Access is denied". Fortunately after google sometime, i am able to find a very useful program to clean up the mess for me, which is called "unlocker"! I'm using the portable unlocker and you can download it HERE. It is pretty easy to use and what you need to do is just open UnlockerPortable.exe and browse through the file or folder you need to delete and follow the instruction.