Since you are already familiar with GParted you shouldn't run into any problem simply calling up the boot device menu if you look closely at the initial post screen or refer to the user guide in order to press the correct F key. That could be the F4, F8, or F12 since F11 is taken there. Once you see the screen you use the NumPad plus and minus keys as well as the arrow keys to move around until the CD Rom or Optical item is selected and press enter to select the optical drive(only one present to find) and press enter to see the live cd booted from.
The other option when going to boot from the 7 dvd itself is to go into the repair tools link found under the Install Now button on that first screen and open the command prompt option. There you would use the manual commands with the Disk Part tool or built-in partition manager to enter the following commands.
Disk Part = opens DP tool
List Disk = lists all hard drives(excluding optical) Your single hard drive would be seen listed as "Disk 0" since you are on a laptop.
Select Disk # = command to select a specific drive which would be "select disk 0" when entered. The commands are typed in lower case at the prompt.
Clean or Clean All = On a desktop with more then one hard drive the Clean All command would be avoided to prevent a major folly! That's the ultimate wipe all drives type command when entered at the wrong time to see all drives wiped clean!
The fast and easy Clean command will remove all partitions on the selected drive only. Once that is taken care of you can then opt to reboot with the GParted Live cd or continue on with one of two choices. 1) You are now ready to allow the 7 installer to create and format the new C primary when selecting the drive and how large that will be if selecting the entire amount of available drive space. The 7 installer will also then create a small 100mb System Reserved boot partition at the front of the drive then seen as "raw" unpartitioned and unformated. The new BCD store and boot files will be placed on the 100mb not on C.
With many the 100mb is unwanted and often people ask how to see that removed and the boot information rewritten over since that contains the boot files there. For seeing just a single C primary and later opting for the Wubi installer where ubuntu is stored as a file on C you can continue on at the command prompt with the next few commands.
create partition primary = creates new primary for 7 to install on.
Format command = format fs=ntfs quick That will perform a quick format of the new C volume to NTFS.
Assign = has Windows automatically assign a drive letter and not used for this however. The 7 installer will take care of assigning C.
Active = sets the C volume as the Active boot partition when avoiding the 100mb System Reserved
Exit = exits the Disk Part tool Entering that a second time closes up the command prompt itself and sees the laptop restart.
If you are still planning to create the second root partition for ubuntu you would bypass the manual creation since it can be awkward trying ot manually calculate the right number of bytes to enter when going to create the new C primary without using up the entire drive space. Most immediately prefer the gui method for seeing the drive split up. But if you are thinking about using the Wubi installer for ubuntu which can simplify things review the information at the site there.
WubiGuide
Here I've used GParted to even split up flash drives to see a small root partition follow a much larger NTFS data partition when creating a live data recovery stick with ubuntu or another distro. GParted will clean the drive off completely when booted live since no OS is loaded to prevent it.