You made the 100gb partition as suggested but installed Win7 to the space to its right. Were you paying any attention to where it was being installed at the time?
There are two ways to solve this. One is to start over, boot the installer, choose Custom install, then on the drive selection screen delete both partitions and create one big one, or just click Next and the installer will do it for you after deleting both partitions. These steps are illustrated here:
Clean Install Windows 7
Or you can install free
Partition Wizard bootable CD, rightclick on WIndows 7 partition to Resize, side the right border to the left to make it 200mb, click OK,
Then rightclick C to Resize, slide the left border to the left to take up the space you just made, click OK, then Apply. This video shows how it's done:
Partition Wizard Move/Resize Partition Video Help.
You'll may need some extra software for your Samsung model. But first continue following the steps in the tutorial to install all Important and Optional Updates to completion - there will be several rounds with restarts. Once that's done look in Device Manager for any missing drivers and import them from the Samsung Support Downloads webpage for your model.
Then test the PC for awhile to see if it is missing any functions as there is sometimes extra software that needs to be imported to install to regain certain functions like Function Keys, Touchpad gestures, Keyboard backlighting, etc. We can help you determine this at that time.