I can say what I used to do in my desktop , you could try and update us whether this really helps,
1.boot with DVD to live cd environment
2.create necessary partition using fdisk like /dev/sda1 - /boot ; /dev/sda2 - swapspace ; /dev/sda3 - / ; format using mkfs.ext3 command and mkswap command resp.
3.reboot , select graphical installation.
4.select manual partition method and skip any format options that are prompted
5.proceed further and normally installation goes smooth