Windows says I'll need as much as 222 GB to create an image. I don't have anything that big. This is the first computer I've ever owned that I didn't have the operating system disc.This is to be expected because Microsoft keeps shipping operating systems that keep system files and user files on the same partition. It is necessary to take some extra steps to separate the two.When you first launched Windows after purchasing the PC, you were prompted to create a set of recovery DVDs.

1. Dell Recovery Disk Windows 7

Dell Recovery Disk Windows 7

At that stage 3 disks would have sufficed.Anyway, a 500 or 1000 GByte disk in a USB case would be big enough. A 500 GByte disk costs less than $60.00. Alternatively you could order a Factory Restore DVD from Dell. There would be an administrative charge.