cannot factory reset

hi all
have been trying to factory reset a dell xps210
with vista as op sys
when get to final stage and authorise it say
Access to \tools\dp.sc was denied
any help to get reset grateully accepted

Try this:

1. Click Command Prompt from the System Recovery Options window.
2. In the Administrator window, type the following lines, pressing <Enter> after each line.
path d:\windows;d:\windows\system32
d:
CD Tools
PCRestore
3. In the Dell Factory Image Restore window, click Next.
4. In the Confirm Data Deletion window, click to select Yes, reformat hard drive and restore system software to factory condition, and then click Next. The message Factory image successfully restored! appears when the process is complete.
5. Click Finish to restart the system.