What I do on my computers is create a 3-4GB partition for the OS and then leave the rest for the programs/files on my pc.
3-4 gigs leaves enough room for device drivers and windows updates while not taking up too much room from the rest of the drive.
What you'll need to do is delete the c partition you already have, then add one partition (I'd label it c) with 4GB and then add a second partition with the remaining space.
Its a frigging Laptop, not a Labtop!!!!