|That happens when you try to access folders or files that were on a different Windows installation and at least one user had a logon password. |
You need to Take Ownership of the folder(s) and files you get the Access Denied message for.
How to take ownership of a file or folder in Windows XP
NOTE: you probably have to reboot the computer before the settings you change actually take effect!
or - you need to use a third party program that can do the same thing.
E.g. Unlocker (freeware)
Works in various circumstances.