So I got a used Laptop a month ago an planned to set it up for my own use. I wanted to set up Windows 10 and Ubuntu on it but have not been able to do so. I would be mention below what I have tried so far. Please take a look and see if I am doing something wrong.
I turned off Secure Boot (So that I could boot from USB).
Set boot mode to UEFI and Legacy from the default UEFI OS. The Third option was CSM OS.(God knows what it is).
Booted my laptop into windows 10 setup on the usb, deleted all previous partitions, created a new partition for the windows leaving more than half unallocated for the ubuntu installation and finally got done with a clean windows installation.
Then I booted my laptop on the Ubuntu setup on usb and launched the installation. For some reason the Ubuntu setup failed to detect existing operating system on the disk and hence did not show me the "install alongside" option. This is where I am stuck. I have tried different ways to proceed from here by going into "something else" option but all my efforts have been wasteful.
In fact I lost windows 10 a couple of times so had to repeat step 3. Perhaps got my boot loader corrupt.
What I understand is the Ubuntu setup must be aware of the existing OS on the machine and something is not letting it to do so. In the "something else" option the only partition I see is my full hard disk as a whole in free space.
Kindly help me with it.