Black screen of death, then I think I made it worst

So my friend's computer had Windows 7. Then one day she turned it off and turned it off and the OS wasn't loading. It just had that white line flashing forever.

So i assumed that I just needed to reinstall the Windows bootloader. So I decided to install Ubuntu then dual boot into Windows using grub. Then once in Windows, I would use EasyBCD to reinstall the Windows bootloader and uninstall Ubuntu. I thought it would work since I did that on my computer once.

Well installing Ubuntu was a bit strange, it detected Windows 7 was on the computer. And I could even go through Windows 7 documents...meaning Windows 7 was fine. But it didn't give the option to install along it. So I chose the advanced partitioner... even though I didn't know what I was doing, I eventually got it installed. But I had trouble getting grub to add Windows 7 to the bootloader menu. So I got fed up and was willing to try anything, so I tried some line of code into Terminal. And now Ubuntu's bootloader is gone. And when I put the live USB into the computer, i could go through Ubuntu documents but not Windows 7.

So does anyone know the original problem and how to undo the mess I created? I also have her laptop with me.

mgorman87 said:

DISKPART and reinstall Windows. It seems like you've gone too far into the hole and the light at the top is just the size of a pinhole. Someone else correct me if I'm wrong, but it's most likely going to involve a lot of work to fix what you've done and the easiest thing to do is format/reinstall windows

I'm not sure what Diskpart is. But I can't reinstall Windows because she doesn't have the disk it came with...I don't even think it came with a disk.