Restoring my Dell Inspiron 8100 to Factory Settings

Ihave a Dell Inspiron 8100, I have checked on the DEll Inspiron 8100 web site, and it gave to directions on how to restory my computer software to its origianal settings. However when I tried it does not seem to work?

The directions are listed here

                                   http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?journalid=6E8D4AC970137D9AE040AE0AB5E12442&docid=336966

When the Dell splash screen appears during the computer startup process, press and hold and then press . Then, release both keys at the same time.
NOTE: Some systems like Inspiron Mini 9 (910) do not support System Restore as they do not have nor any substitute

Is this correct or am I doing something wrong?  My pc just boots into windows, and does not seem to go to systme restore.

Thanks

  Herman