Downgrade from Win 8.1 Pro to Win 7 Pro (Inspiron 3847)

Yes it is permitted to downgrade Win8 Pro to win7 Pro.  You use a Dell OEM WIN7 64 bit Pro SP1 DVD.  Dell however is not obligated to provide the media.  If you ask they may send it to you.  Depends on your country.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=%28DELL-WINDOWS-7-PROFESSIONAL-REINSTALLATION-CD-DVD-64BIT-SP1&_sacat=0

Use a Digital River .iso with the ABR program and Dell OEM cert files as described here:

http://dellwindowsreinstallationguide.com/download-microsoft-windows-and-office/download-microsoft-windows/windows-7-sp1-iso-download/

This will give you a Dell Windows 7 Professional Reinstallation DVD with Dell OEM SLP activation and its the only way you can legally downgrade a Dell Windows 8.1 Professional OEM as you have no unique key as the system won't have a Windows 7 professional COA.

The Digital River servers have been a bit unreliable the last few days so ensure that you download the full .iso. and don't just get a partial download.

http://support.dell.com/support/topics/global.aspx/support/kcs/document?docid=590895&DoNotRedirect=y

 During the process of installing Windows 7 Professional, removal of the Windows 8 partitions is required (Windows 7 cannot be installed on Windows 8 GPT partitions).  This is why you need a 16 gig flash drive to make a full recovery media. If the hard drive in your computer cannot be found, you may need to install the Intel Rapid Storage Technology or other hard disk drive controller driver (PERC H310/H810 etc.) from a USB key you previously created for this installation. See the LOAD DRIVER section at the bottom of the Windows 7 install screen to load the drive controller driver. This replaces the F6 method from previous versions of windows.

My 3847 that I got at christmas came with windows 7 PRO Pre installed with DBAR 1.6 with a windows 8 Pro Color changing Sticker.

After Testing various scenarios I came to find that DBAR 1.7 does not have the Tatooed drive issue or the Drive size issue.  DBAR Needed 10.3 Gigs on the USB Flash Drive.  This is why I say 16 Gigs OR Larger.  My new Goto flash drive is 128 Gigs $50 from microcenter.

So once I upgraded to DBAR 1.7 i was able to "recover" onto various Drives as small as 80 gigs and get it working again.

I was shocked and disappointed that the system came with a tiny text manual that I cant read because its too small text for me to see AND had No resource or Restore Media.

Being a windows 8.1 system with no coa that means that I  needed to download an ISO from microsoft and make a bootable 8.1 flash drive.   Drivers were hard to figure out however. There were complaints from the drivers listed on the Dell site that my system was not the right one bla bla bla.

I was able to upgrade from the G3XXX series to a 4th Gen Core I7 and 16 gigs of ram and a Radeon R7 250E aka 7750 and everything works just fine.

That issue was fixed in 1.7.1.2 as we had asked for the ability to perform the install from a 1 TB to a 128-256 GB SSD. 1.7.5.64 had fixed some issues when using DBAR on a clean install because the recovery partition was given a drive path in Windows explorer. I think theres a major update planned sometime in March which I am looking forward to testing. I now have some hardware capable of video capture within the Dell BIOS. When I buy a new Dell system with a UEFI BIOS I will make a new guide on Dell Backup and Recovery because as you've stated the documentation lacks.

With the Windows Media Creation Tool its easy enough to switch back to Windows 8.1 Professional. On the other hand its harder to manually exhibit downgrade rights to Windows 7 professional if Windows 8.1 Professional is preinstalled because no Windows 7 Reinstallation DVD is included. The Digital River .iso does not include Dell OEM SLP and there is no COA so no unique Windows 7 Professional Product Key. The use of the ABR program and backed up Dell cert files is a valid workaround for this and works very well but as a lot of things in my guides regarding installation media is still unofficial but of course works better than official solutions.

This is the Desktop Audio board. This question should have been moved to the Microsoft OS Forum? In the future, let me know via PM and I will move them for you.