Hi, and thank you for asking your question.
You may purchase a brand new Windows 7 installation disk online from Amazon, using the following link:
Having gotten the disk, you just need to boot up your system with the installation disk inserted and follow the on-screen directions to install Windows 7 accordingly. Please note that you will only be able to carry out a FRESH installation of Windows 7 - it will not upgrade over the previous Vista installation, so you will need to make sure to back up your files first, before installing Windows 7.
If you need more help, please use the Reply tab to continue our conversation.
Otherwise, I'd appreciate it if you could kindly take a moment to RATE my service by clicking on (and submit) a star rating at the top of this page. Thank you!