If you need the key only for product activation see here: [URL] and here: [URL] If you need to clean install you need either a Windows 8.1 retail .iso which requires separate purchase of a Windows 8.1 retail license, borrowing from a friend or from unofficial download sources (unrecommended) or you need to request a Dell Windows 8.0 Reinstallation DVD/USB (recommended). If in the US or CA you can fill out the following form: www.dell.com/recoverymedia If outside these regions you must call Dell Technical Support.
Could you please help me one more problem. My laptop is copyright OS 8. When I devided the 700GB partition  into 3 partitions (C, D, E) for the desired capacity (100GB, 300GB, 300GB).  But then OS cannot be opened. I have converted disks from GPT type to MBR  format to install new OS but accidentally merged partitions recovery into other partitions.  Now I even cannot use the initial OS. Then I installed  OS 8 from Dell (as I know  the copyrights OS embedded in the BIOS of the laptop).  And i have tried in vain many ways to recover the key copyright OS. Could you advise me to solve the situation to return to the original OS.  Could you please check the Dell system the key of this laptop. Looking forward to your help .   Thanks in advance
Recovery Copyright OS 8 when merged partitions recovery into other partitions