If you have this Dell, be careful about the current update, multiple users have the problem. Quoting the Register article:
As one forum wag noted: “Some send out ‘WannaCry’, others send out BIOS upgrades”.
https://www.theregister.co.uk/2017/05/18/dell_bios_update_borks_pcs/
http://en.community.dell.com/support-forums/desktop/f/3514/t/20012309?pi21953=1
http://en.community.dell.com/support-forums/desktop/f/3514/p/19435778/20050222
PS: These are nice references from Dell’s support wiki:
http://en.community.dell.com/support-forums/desktop/w/desktop/3634.extremely-long-psa-code-chart