I have installed Ubuntu 12 from a USB drive and after the installation my laptop did not boot from the HDD anymore. Before the Ubuntu installation Win7 was installed. During the installation I choose to delete the Windows installation. I searched here (SU) and on the web and ended up in this guide.
This is the screen in the first place of the partition manager with out making any changes.
from the size of the partitions I can say that "/dev/mapper/ubuntu-root" was the "C" partition in Windows and "/dev/sda" was the "D" partition.
and this is the screenshot. I could manage and tried to make it similar to the guide.
but it did not do anything. I can not delete the partitions using the manager. I can only change the type and mount info.
Thanks for your help.