reinstalling windows question-pls help

[Tattooed]

Hi,
needing some advice. My laptop came with Windows Vista pre-installed. I upgraded it to Windows 7 upgrade version which i have had installed since Christmas. I would like to reinstall Windows 7. Now- do I have to install Vista first then Windows 7? or just reinstall Windows 7?

 

[mcompute]

Do you have the Windows 7 install disc or is in an upgrade only disc?