It's my again, I was trying to solve my problem of dual boot in Ubuntu, because in the Grub I didn't have windows to boot. So the community sent my into this link "How can I change/convert a Ubuntu MBR drive to a GPT, and make Ubuntu boot from EFI?"
I was trying to follow the steps to do it, I wanted to use the flashdrive where was installed Ubuntu to boot since windows. So erase a file, I shuttled down and Ubuntu sent error message and when I restart the system I have windows on my screen and I was scare. Please community, what do you think that I must do? Erase the partition where is Ubuntu in Windows and install Ubuntu again? or return to Ubuntu and make Ubuntu boot from EFI? I don't have CD driver to make a backup.