I have LENOVO Ideapad z570 model. when ever i try to install ubuntu(any version 12.04,12.10 or 13.04) it say "no operating system detected" but i have Windows 7 installed on it. And under the option "Something else" it shows whole 1 partition of 750GB hard drive but i have 2 partition. I tried to create new 10GB partition from that 750GB of partition and installed unbuntu on that 10gb of partition, it erased all my data and all the partition. What am i supposed to do to install ubuntu?