this is what just happned. I was talking with my girlfriend on Skype, trying to save her old computer. Basically, she had Windows installed and it didn't boot anymore. Also not in SafeBoot mode. Her computer didn't react to her CD-Drives, which is why we couldn't reinstall it.
So, I asked her to use a Linux Mint Live USB Thumb Drive to check if it boots. Basically I wanted to check if the computer still works. Linux started just fine.
Okay, here's the tricky part. My plan was to install Linux Mint on this computer. Download Windows with it and put the iso per dd on the thumb drive we've used to install Mint with.
But this is what happened and keep in mind, I have walked her through the steps in Skype. I didn't see the system and she chose to install the system in Russian and I gave her the walkthrough in English, so she might have chosen the wrong option. But I don't know which one could have been wrong.
She had Linux Mint running via Live System, got the option of installing it side by side with Windows, but chose to delete it instead. The installation ran through, I saw the installation bar filling through Skype. And when it was done, she told me it said successful and restart. She did restart, but not remove the flash drive and therefore it started into live mode again. I told her to turn the computer off, remove the flash drive and Windows was starting again. Nothing was deleted.
And I don't get what just happened. Can somebody tell me how this could have been. I am not looking for the exact explanation, only one that would make this reasonable. Because it looks completely random, almost magic to me. And therefore I am quite startled.
UPDATE: Grub wasn't installed. The hard drive owns just one partition. The one with Windows.