I am using Dell Inspiron 17R with Windows7 as the primary OS to boot my system up. I am new to Linux and to begin with, I thought of installing Ubuntu 12.4 AMD 64 bit version on my laptop. Today I performed a successful installation on my laptop but when I reboot, it doesn't show me the Ubuntu OS in the list (I can only see Windows7). Is there any way to bring up the Ubuntu entry into this list? While installing I selected the option to have both Windows7 and Ubuntu OS on my laptop. The root drive for both OS is C: drive. Hence I split the drive into two (250 GB for Windows7 and 250 GB for Ubuntu). Now I can only see 250GB in my C:\ drive for Windows7. Is the remaining 250GB assigned to Ubuntu or did I lose that 250GB space?? Your answers will be highly appreciated..