Reading through the gparted forums there seems to be some support issues for hdmi connections. One solution is to use a vga cable while using the gparted live cd. Another suggestion was when you get to the white screen you mention hit
this should drop you to a console. Then type in
it will give an option for video drivers try
it is a good failsafe. Then it will give you an option for resolution. You can enter one or if you just hit enter it will load the default resolution.