It's a bit hard to give meaningful advice when your profile indicates you're using an operating system and Office version that have long since ceased being supported. If you're not using Office 2000 on Windows XP, please update your profile.
If your system has different users accounts, you can set the access permissions by file and/or folder. See:
https://msdn.microsoft.com/en-us/lib...or=-2147217396
In addition, Office Applications can also password-protect their files and software such as WinZip allows you to encrypt files of any kind - as well as its core function of compressing files.