Set up a Guest Account
If you're like me you never do anything important without bringing a backup laptop. Sometimes someone may want to borrow that laptop. Here's how you can do that safely.
If you got Control Panel and type in Add or Remove, you should see the option for 'Add or remove user accounts'. Click on this and you'll see an option for a Guest account, which you can turn an off.
You then want to restrict which folders the guest account has access to. You can prevent the guest user from accessing any data saved on your C drive, by right clicking on the drive, selecting Properties, and going to the Security tab. On this tab you'll see a list of user names. Select the guest account and then click Edit.
. . . a new window will open and you'll see you have the option to either grant or deny the guest user full control of a folder or more specific modify or read rights.