Answer
This question was answered on June 29, 2007.
Much of the information contained herein may have changed since posting.
First, you must use an Administrator account. So long as you didn't specify the account to be limited when you setup XP Pro, you should have no problem.
Second, you must disable Simple File Sharing. By default, Windows XP Professional uses Simple File sharing when it is not joined to a domain.
1. Click on the Start Menu and go to My Computer.
2. On the Tools menu, click Folder Options.
3. Click the View tab, and then select the Use Simple File Sharing (Recommended). Clear this check box to turn off this feature.
Now locate the folder(s) that contain the files that you want to copy.
To take ownership of a folder, which allows you to copy the documents, follow these steps:
1. Right-click the folder that you want to take ownership of, and then click Properties.
2. Click the Security tab, and then click OK on the Security message (if one appears).
3. Click Advanced, and then click the Owner tab.
4. 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 subcontainers and objects check box.
5. 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.
6. Click OK, and then reapply the permissions and security settings that you want for the folder and its contents.
Now you should have no problem getting to your documents!