A fatal error when install ubuntu after win7

[nullne]

sorry for my poor endglish.
long time ago,i installed ubuntu on the whole hdd,later,for some reason,i installed win7 only.now ,i wanna install dual system,so it is that installing ubuntu on win7.

but when i reboot from my ubuntu12.04 usb-installer,it appeared that this computer has no currently detected os.
so i donnot know what to do next.

waiting for help,thank you

[Rubi1200]

Hi and welcome to the forums :-)

To help us determine what is happening, please do the following:

1. from the LiveUSB, post a screenshot of how GParted sees the drive.

2. post the results of the boot info script (see bottom of my post for a link with instructions)

Thanks.