I have a dual-boot Windows 7 and Ubuntu 14.04 system that I originally installed using Wubi. I have heard that it would be beneficial to migrate my Ubuntu installation as described at How to convert Wubi install into regular install?. However, when I try to unmount /dev/sda3 (the partition I want to use for Ubuntu), I always get a message saying it's in use. Also, I think I remember making some partition-related choices during the installation process. Could it be that my Ubuntu installation is already on its own partition? If not, what do I do about /dev/sda3?
Here's the output from parted -l.
Model: ATA MB1000EAMZE (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 1049kB 651MB 650MB primary ntfs boot
2 651MB 271GB 271GB primary ntfs
4 271GB 274GB 2146MB primary linux-swap(v1)
3 274GB 1000GB 727GB primary ext4