Turn off Simple File Sharing:
Click Start, and then click My Computer.
On the Tools menu, click Folder Options, and then click the View tab.
Under Advanced Settings, click to clear the Use simple file sharing (Recommended) check box, and then click OK.
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, 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, click to select the Replace owner on subcontainers and objects check box.
You may receive the following error message, where Folder is the name of the folder that you want to take ownership of:
You do not have permission to read the contents of directory Folder. Do you want to replace the directory permissions with permissions granting you Full Control? All permissions will be replaced if you press Yes.
Click OK, and then reapply the permissions and security settings that you want for the folder and the folder contents.