Installed Windows on separate partition and now cannot boot Linux
I originally had my full hard drive as a full Ubuntu partition but I then re-sized that and installed Windows on a new partition. Now I guess the boot sector got overwritten and I don't have a choice to boot either Windows or Ubuntu. I know I have to reconfigure GRUB or another boot loader to allow the choice but I am not sure of how to go about that.
Thank you in advance for your help.