Find out what version of W7 you have (probably home permium)
Then google the link for 'Digitalriver windows 7 download'
Get the Windows 7 Home Premium with SP1 iso file
Use IMGBurn to burn this to disc, use your product key to install it.
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Set your BIOS to AHCI mode for the SATA controllers, you'll get better SSD performance with this on.
I have it turned on on all of my machines. Make that change before installing Windows. If you do it afterwards, it'll stop Windows from booting without a little fiddling..