How to Restore Dell Inspiron 1525 to origonal factory settings ?

As instructed to do by many forums I press F8 to bring up the advanced boot options as my computer starts. From there I am told to select "repair my computer" the problem is this option isn't available and I'm having trouble finding other optionsseeing as all my  software was pre installed and i have no disks, for clarity when i open the advanced boot options page this is what I see 

Safe Mode

Safe Mode with Networking

Safe Mode with Command Prompt

Enable Boot Logging

Enable low-resolution video (640x480)

Last Known Good Configuaration (advanced)

Directory Services Restore Mode

Debugging Mode

Disable automatic restart on system failure

Disable Driver Signature Enforcement

Start Windows Normally

I don't know if this is relevant but I recently upgraded from vista service pack one to SP2