Are you dual booting?and if you arent, just use the install it now or whatever
Looks like you haven't set up an unused partition. That looks like a very standard UEFI formatted hard drive.
I am trying to install Elementary, but I can't figure out which partition is which.My HDD is 500 GB.
just hit the dual boot with windows 7 option from the installation menu, it partitions for you
also sda3 is your 500gb hard drive
Its one of the three partitions on the disk