They are no longer supplied with new systems -- you should, however, make one.  Open the Dell backup and recovery utility on the system.  The easiest way to do this is to use a 16G or larger flash drive you can dedicate to the task (the other way is with a set of DVD-R or DVD+R discs, but you'll need several of them).

http://www.dell.com/support/contents/us/en/19/article/Product-Support/Self-support-Knowledgebase/software-and-downloads/dell-backup-solutions/Dell-Backup-and-Recovery

ejn63 is correct, they no longer send disks out, but you can get disks by going here or just call Dell. That's what I did a few weeks ago. I told them I needed a reinstlation disk and a drivers disk. They sent out out both, no problem.

Copy and paste link into your browser to have a look. I actually would call though, and be sure to tell them you need both disks. The W-7 one & the disk with the drivers installed on your computer.

https://www.dell.com/support/diagnostics/us/en/19/nondiagnostichome?c=us&l=en&s=dhs