So far I've tried
- using Disks in ubuntu applications. At first it appears as if the partition is indeed deleted but when I restart my computer I still get the choice to start in windows and doing so I am taken straight to a repair site.
- I installed gparted and deleted the windows partition there and again it appears as if the windows partition is deleted but when I restart again I get a choice to start up in windows and this time there's not even a repair screen I am just taken straight to windows as if nothing happened.
What I want to do is delete the windows partition completely without a trace of it. Please let me know what I am doing wrong!