Uninstall KB2871389 and reboot.
Download KB2871389
Install and reboot.
8.1 should now appear in the Windows Store
Source: Dell Community
Category Archives: Dell
Re-install Adobe software that was pre-installed on Dell PC
Run the Dell Smartsource tool:
https://smartsource.dell.com/Web/Welcome.aspx?ReturnUrl=%2fweb%2fmain.aspx
Shortcut to DELL drivers Australia
Reply
http://www.dell.com/support/drivers/au/en/aubsd1/ServiceTag/xxxxxxx
Where xxxxxxx is the service tag.
Find DELL service tag via command line
Command Prompt:
wmic bios get serialnumber
Source: The Geek Stuff