I've just installed Ubuntu (14.04 LTS). Before this, I had dual-boot Windows 7 and Fedora 18, and I tried to uninstall the Fedora, but I did something wrong, so I have to install Ubuntu (because I have its boot CD). I chose to install Ubuntu, and then "Erase disk and Install Ubuntu". Now I cannot open Windows 7 again, as it immediately runs Ubuntu when I turn on the computer. What I want to do now is to check whether there are some files left from Windows 7. Of course, those files aren't important. I just want to make sure that there aren't. How can I do this? Sorry for my English Thanks
Since you selected the option
Erase Disk and Install Ubuntu, the hard drive was formatted as an ext4 partition and hence no Windows related files are on it.
However, data can still be recovered using tools such as
photorec and hence if you want to completely get rid of your previous data, it is recommended to
zero the hard drive, ie overwriting with zeros.
"Erase disk and Install Ubuntu".
This means "remove any and all other operating systems and install Ubuntu".
Now I cannot open Windows 7 again, as it immediately runs Ubuntu when I turn on the computer.
That is because you removed Windows 7 (and Fedora). When there is just one operating system on a computer it will automatically boot that operating system. When there are 2 or more you get to choose when booting.
Of course, those files aren't important. I just want to make sure that there aren't. How can I do this?
If you want to check the lay-out of your disk you can install "gParted" and see if there are any partitions labelled as "ntfs". Those are Windows partitions. But I doubt if there will be any.
But in general: foreign partitions will be automatically shown in the launcher after the initial install (the icon is a grey harddisk icon). If those are not there you can also assume there are none on your disk.
If you chose to "Erase disk and Install Ubuntu" during your ubuntu installation there can not possibly be any windows files left .
Because in the "Erase disk and Install Ubuntu" step the installer formats your hard drive while converting it from NTFS(default windows file system) to ext4(ubuntu 14.04's default file system).
Unless you lost some important data and are looking for ways to recover it.
You really shouldn't be worried!