Ubuntu Linux, just like most Linux distributions, will happily co-exist on a hard disk 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 which provides the option to boot either Ubuntu Linux 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 Linux regardless...
