I will tell u how to lock old document in XP
after re-install or upgrade your XP, you can’t access your old My Documents folder? Don’t panic, easy..
One have to do is take ownership of that folder where you have been denied access with replace the security permissions to have access.
First, you must be logged on to the computer with an account that has administrative credentials. If you are running Microsoft Windows XP Home Edition, you must start the computer in safe mode, and then log on with an account that has Administrative rights to have access to the Security tab.
If you are using Windows XP Professional, you must disable Simple File Sharing. By default, Windows XP Professional uses Simple File sharing when it is not joined to a domain. For information about how to disable Simple File Sharing, view this Microsoft Knowledge Base’s article about it.
Now, follow this steps to take ownership of a folder:
Right-click the folder that you want to take ownership of, and then click Properties.
Click the Security tab, and then click OK on the Security message (if one appears).
Click Advanced, and then click the Owner tab.
In the Name list, click your user name, or click Administrator if you are logged in as Administrator, or click the Administrators group. If you want to take ownership of the contents of that folder, select the Replace owner on sub containers and objects check box.
Click OK, and then click Yes when you receive the following message:
You do not have permission to read the contents of directory folder name. Do you want to replace the directory permissions with permissions granting you Full Control?
All permissions will be replaced if you press Yes.
Note folder name is the name of the folder that you want to take ownership of.
Click OK, and then reapply the permissions and security settings that you want for the folder and its contents.
Hoopla! Now, you’re grant access to your old My Documents folder!
i hope u clarify ur doubt after read this post