No sdb partion when trying to dual boot Ubuntu 16.04 with Windows 10

Question

I'm trying to create a dual boot with Ubuntu 16.04 and Windows 10 on my Inspiron-15-3000 series following this tutoriel in French made by Playmatic24

I didn't achied it when notifying many differences :

• I don' have a partition sdb along an sda
• I think I disactivated the UEFI when uploading Ubuntu 14.4 for the fist time one year ago and some messaged pop-uped to warn me about something about it. May I follow up installation if I clicked on "not to force the uefi mode installation" ?

Here is a screenshot of the option where I stopped before choosing the "other option" installing option. - I had a weird "ubuntu" option for booting in the grey and blue screen. Maybe it is normal because of my first Ubuntu 14.4 or 16.4 installations ...

My question is : may I have continued by partitioning with the three mounting option (for /, /home and the lastion I don't remember the name...) or do I miss something?

I tried then this tutorial in English from everydaylinuxuser.com, changing my fast boot option and secure boot option to down and now I'm not able to boot on Windows anymore, even from the blue and grey screen.

Update 2/5/2017

Here is the boot info :

http://txt.do/drvsx

Answer 1

I don't speak French, so I can't follow a French YouTube video. That said, I have some comments on your query:

• /dev/sda and /dev/sdb are entirely separate physical hard disks, not partitions. If your guide showed both but you have just one, it means that you have fewer hard disks than whoever wrote the guide. (The installation medium itself might show up as /dev/sdb, though, which can complicate the comparison.) Partitions are numbered and referred to with numbers following the disk device filename, as in /dev/sda2 or /dev/sdb4.
• As a general rule, if you want to dual-boot Ubuntu with an existing OS, you should NOT adjust EFI/UEFI vs. BIOS/CSM/legacy boot options. See my page on the CSM for a detailed presentation on why this is so.
• It's hard to tell from your description how your computer is set up. To provide detailed information, please run the Boot Repair utility and select the "Create BootInfo Summary" option. (DO NOT click "Recommended Repair," at least not yet!) When asked whether to upload the report, click "Yes," and then post the URL provided here.

I recommend you read the following pages:

• Adam Williamson's blog entry on how EFI works -- This page describes the theory behind EFI-mode booting.
• A question and answers on the differences between BIOS and EFI booting on Superuser.com -- This provides the basics of the preceding, but is more concise.
• My page on installing Linux on EFI systems -- This page is a more practical introduction to EFI-mode booting than Adam Williamson's blog.
• My page on the CSM -- This page covers the CSM, including when it's useful and when it's not.
• The Ubuntu community wiki entry on UEFI -- This page is a bit disjointed, but is the most Ubuntu-specific introduction to EFI and its issues.
• This site's question on installing on EFI-based systems -- This is yet another EFI-mode installation guide.

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EDIT: Your existing Windows installation is definitely in BIOS/CSM/legacy mode. As such, you should not attempt to install Ubuntu in EFI/UEFI mode. To avoid doing so, you must learn to control the boot mode of your computer. This involves both properly creating your boot media and somehow selecting the boot mode used to boot an individual medium. Typically, you'll see two options for a USB drive, one with the string "UEFI" and one without it. Selecting the one without "UEFI" is the appropriate choice. Read my page on the CSM (referenced above) for more information; however, that page is written mainly for people who have EFI-mode Windows installations and who might be tempted (through frustration or bad instructions) to install Linux in BIOS mode. You have the opposite problem.