Before you begin...

First of all, a word of caution: Folder Guard is a powerful tool that should be used responsibly. Using it thoughtlessly, you can inadvertently make your computer inaccessible. For example, it is very easy with Folder Guard to prevent access to the Desktop folder, and make Windows start with a blank screen after you reboot. To avoid such surprises please do the following:

Before you begin using Folder Guard, backup your entire hard drive or at least the most important documents and the system files. It is a good practice to backup your files on a regular basis, as well as before installing any new software!
Make sure you know how to boot Windows in the safe mode and know how to use the computer in that mode. Folder Guard is not normally enabled at Windows startup in the safe mode, so you should be able to bypass it and correct any problems. (And yes, you can configure Folder Guard to protect your computer even in the safe mode, click here for more information.)
Create a practice folder somewhere on your hard disk (such as C:\Test), copy some files into it, and try to protect that folder first. After you get used to the way Folder Guard operates, you may start protecting other folders that contain the files you actually want to be protected.
Do not assign the no access attribute to the C:\Windows folder, unless you know what you are doing, because that will make Windows unable to use its own files! Do not restrict access to the whole C: drive, because other programs located on that drive would stop working! Let us repeat: Folder Guard is a powerful tool that should be used with care.