yup just install it on the new pc with your product key and then transfer the spreadsheets themselves over. it'll all pick up right where you left off. the program and the spreadsheet you work with are not tied to one another.
While there are ways to extract your license key from (still working) laptop, you will need an installation media. There's no Excel 2009, probably you have 2007 (you can check that on your laptop), and you will need CD/DVD with exct version.