I have a computer with Windows 7 and Ubuntu working well, but after having trouble with Ubuntu I decide to make a fresh installation with a bootable usb. When the point came to choose in which partition to install it, Ubuntu didnt recognise Windows, so I created the partitions for / and swap and installation finished fine. When I tried to boot it, it took me directly to grub command line. After booting again and hitting F12 I could see the Windows Boot Manager was still available and it booted without any problems, but I still can not access Ubuntu. I tried installing again with the same results. How can I install GRUB correctly so it recognises Windows and Ubuntu? The booting system is UEFI.