Thanks for your replies guys. Actually the problem would have been easy to solve if I didn't try so many boot changes first. The last update change a UEFI setting from ahci to raid. Just change it back to ahci and everything will go well.   I went for a fresh new installation and once the last updates happened, the problem came back and I solved it as I explained.   Thanks for this weird update Dell ... I had fun for a week and still is reinstalling some programs ...
Hello,    I have a Dell Inspiron 15 7000 2n1, version 7506.   Since my last updates on my windows system (including a bios flash update), my computer doesn't boot. It goes to this nice weird screen with a not smiley face telling you "your device .... Needs a restart". Then it loads the troubleshoot option (with choosing keyboard first) If I try a startup repair : 'couldnt repair your PC" If I try anything else ... Same answer  So I started the os recovery tool (F12) and tried twice already to repair the system ... After loading the tools and repairing, no errors, it says it has been fixed and that I can restart however still doesn't boot. I am thinking of trying a reset however I am afraid of loosing my data ...  Here are my questions :  - is the backup for the reset done online or on a external disk ? (I have 700Go of data .... Seems big to backup ...) - should I try to boot on a USB with the last bios update first ? And what is the procedure exactly ?   Thanks for your help ... Already 4 days without computer ... I really hope yo fix it and Im pretty ok with computers normally ...
Boot issue