5. Dual Booting Ubuntu with Windows
Ubuntu, just like most Linux distributions, will happily co-exist on a hard disk drive with just about any version of Windows. This is a concept known as dual-booting. Essentially, when you power up your PC you will be presented with a menu providing the option to boot either Ubuntu or Windows. Obviously you can only run one operating system at a time, but it is worth noting that the files on the Windows partition of your disk drive will be available to you from Ubuntu regardless of whether your Windows partition was formatted using NTFS, FAT16 or FAT32.
During the installation process the Ubuntu installer will detect the Windows installation on the drive and provide the option of deleting it and using the entire disk for Ubuntu, or sharing the disk with Windows. In the latter case you will be able to specify the percentage of the disk to be used for Ubuntu.
According to the Ubuntu documentation, a minimum of 25 GB of disk space is required...