I'm trying to install xubuntu 14.10 on a computer which has windows 7 installed already. I want the xubuntu to resize the existing Windows installation and install alongside it giving me a dual boot system.

I've created a standard USB stick from the 14.10 ISO file and it boots OK in the new computer but doesn't 'see' the existing Windows installation. It does see the two existing NTFS partitions OK though.

Does anyone have any idea why the Windows installation isn't recognised and/or how to get xubuntu to install as dual boot?