The option to format the drive is "hidden" in "Advanced drive options" (or "advanced options" on some versions of the installer.)
I personally recommend formatting the drive as a separate operation on another computer AFTER you use the installer to delete the current partition as well as the little 100mb "system reserved partition"
This partition should be around 110gb (Anything larger is wasted)
Then when running the installer from the ROM disc install the OS in that partition
and the windows installer will not create that additional partition but instead include the "system reserved" within the OS partition.
The advantage to doing this is it makes it far easier to migrate to another Drive using an "image" of the system. normally a system image that is separate from that 100mb "System reserved" partition will not be bootable after mounting the image to another drive until you again run the windows installer disc and choose the "repair windows" option and run a "Startup repair"
Basically what I'm saying is that not allowing the installer to create the partition itself and thus not making that 100mb system reserved partition will make it far easier for you to migrate to an SSD at some later date.
Another thing to watch for is to look inside your bios settings (in setup) and see what mode your ATA controller is set to, if you have the option if setting it to AHCI mode before reinstalling windows, do so...