Some malware do change your files' attributes to system/hidden but when you want to change them back to normal you wont be able to do that because the options are grayed.

iReset is an intuitive application that will reset any system or hidden files, thus allowing you to access them normally.

How to use it?
Simply drag & drop your files/folders into the cross sign and then click RESET.

NOTE: This tool is for FREE for personal use only!