Reinstallation DVD needed

Hi,

I am trying to repair my windows 7 on laptop but the original DVD Reinstallation disk is faulty or scratched.
it gets to 60% and then hangs. i am looking for a replacement reinstallation DVD for my Dell pc.
My laptop is Dell Latitude E6410.

I cannot see a direct email address for Dell.  How much would a Reinstallation DVD be ?

thanks

gaz