Is your laptop still working? What exactly are you trying to do?
Are you trying to just start up your laptop? Or are you trying re-install Windows?
There is not a 'download windows start up disk' available that I know of but you can order "a set of backup discs containing the factory-installed operating system as well as the device drivers and utilities specific to your system"through Dell Support
You could also use another computer to build a bootable CD.