I have i7 7th gen with nvidia GTX 1050 with 8GB ram, 128 GB ssd and 1TB hdd. I had just win 10 installed on my SSD then i installed ubuntu 18.04 lts alongside windows without swap on my HDD. I couldnt shutdown or reboot my ubuntu so I formatted ubuntu partiton from win10 disc manager then when i rebooted it showed GNU GRUB2 error. I can boot into windows so I tried installing Ubuntu 16.04 on the same drive as of ubuntu 18.04 (this time with swap partition). But I dont think that worked and i see the same grub2 error screen again. I can give windows boot manager upper priority and boot into win. But how can i fix my grub or completely remove it from my system?
I recently did something similar, and I just wanted to get back to Windows only. You need to fix the boot record of your disk - something like https://www.easeus.com/partition-master/repair-mbr-windows-10.html or https://www.pcworld.com/article/3113585/windows/how-to-repair-windows-master-boot-record-and-fix-your-bricked-pc.html
What I ended up doing was:
- Use ubuntu live usb stick to erase the ubuntu partitions and resize the windows partition to use the new free space - I used gparted for this.
- Create a windows 10 installation usb stick and repair the boot record.
I strongly recommend having a second system available to create usb sticks and google stuff.