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/3624.beep-codes-and-psa-diagnostic-chart

http://en.community.dell.com/support-forums/desktop/w/desktop/3634.extremely-long-psa-code-chart