Buy a new hard-drive for the laptop
http
/www.newegg.com/Product/Product.aspx?Item=N82E16822136280 , install Windows 7 on the new drive http

/www.newegg.com/Store/SubCategory.aspx?SubCategory=368&name=Operating-Systems. Buy an external enclosure for the old drive to copy your data over and as a backup http

/www.newegg.com/Product/Product.aspx?Item=N82E16817729011.
It looks like that laptop has drivers available for Windows 7 so you should be fine.