Well, didn't understand actually is your device locked down by the PIN and yo forget the PIN or your device folders is locked by some PIN because you are using some application to lock down those files and folders ??? Anyway if you're device is locked by PIN then you can try unlocking your device by using the gmail account which is set up at the start i.e. the very first time you power on your device (Your device must have an active data/wi-fi connection for this trick to be working). If the data/Wi-Fi connection is not enabled then also there is no need to worry, while the device is locked keep pressing the power button until a popup appears asking wether you want to switch your device off, etc there should be a option name data connection enable tap over that an you data connection via mobile network will start working. I am sure you can use it to unlock your device !