Use the Dell DataSafe Local application and create an emergency recover USB stick. The USB drive will need to be approx. 8GB in size. Once you have it, stash it away somewhere safe. This will contain your factory image.
You can also access the factory restore by booting into the Windows Recovery Environment using F8 @ the BIOS screen.
If you have further questions, post them here, we already have a thread on the Recovery Partition: M11x Recovery Partition