I'm pretty sure the "Not Initialized" means you have not done the required 2-step process. I checked the Samsung site and cannot find any good utilities there for you, so here's the process using Windows' own tools. To do this you will need your old drive installed as the boot drive and be able to boot into Windows from it. Your new drive also needs to be installed in your machine as an internal drive. As you say, it will not be available to Windows and will not show up in My Computer, but the BIOS should see it.
The process below will prepare your new drive for use as a data drive, but NOT as a bootable drive ready to replace your old drive. For that you need a utility that clones absolutely everything from old to new drive, allowing for an increase in the size available on the new drive. (See end of this post for info.) The steps below are for Windows XP; I understand VISTA is similar.
With Windows running, start by clicking Start at lower left. On the resulting window, about middle of the right side, RIGHT-click on My Computer and choose Manage from the menu. In the resulting Computer Management window on the left, expand Storage if necessary and click on Disk Management.
On the right you will have two window panes, both scrollable if they have enough stuff in them. The upper one has all the storage devices Windows is using now. The lower one has those, PLUS any new devices Windows still cannot use, like your new drive unit. RIGHT-click on that new drive and choose Partition from the menu. BE VERY SURE YOU ARE PARTITIONING THE EMPTY NEW DRIVE, NOT YOUR OLD DRIVE!! In the resulting window(s) choose the size of the new Partition you are creating (I presume you will want it to use ALL of this new disk in one Partition), make this the Primary Partition, but do not make it bootable. When your options all are set, proceed with the operation. What this does is create at the start of the disk a brief table showing where each Partition begins and its size (probably only one Partition), and whether it is bootable.
IF you chose to make the first partition smaller than max, after this first operation is done you will see the drive with some Unallocated Space. In this space you can use the same tool to create a second Partition (or even more), but they won't be Primary Partitions, and won't be bootable.
When that operation is finished, come back the the new drive and RIGHT-click it again. This time choose to Format it. The choices to make are to use the NTFS File System, and whether to do a Quick Format or a Full Format. (IF you chose to make more than one Partition on this device, each Partition needs to be Formatted individually). A Quick Format establishes at the start of the Partition a Root Directory and all the hidden files needed to track the allocation of disk sectors to files. It typically takes 5 to 10 minutes. A Full Format does all that, then runs a full test of every sector on the disk to be sure it works properly. Any faulty sectors found are marked never to use (rare to find any). This process will take MANY HOURS, so maybe let it run overnight.
When the Format is finished, escape back out of the menus and reboot. When Windows is running again, look in My Computer. The new drive should be there with its own letter name showing no files but ready for use.
If you want, instead, to move everything from old to new drive so it becomes your new boot drive, check out Acronis True Image at:
http://www.acronis.com/homecomputing/products/trueimage/
Click on the User Guide link (it will download the .pdf file) to read what it does and how. Concentrate on Chapter 13 about moving everything to a new disk. Back on the first web page, click either on Buy Now or Free Trial to get it if that's what you want. Acronis True Image is a very good utility with lots of useful features beyond cloning to a new larger drive. If you go this route, just start with the drives installed and Windows operating, per my first paragraph. Then download and install Acronis True Image and use it, ignoring all my notes about how to use Windows' Disk Manager for setup.
There are other drive cloning / migration tools availalbe on the web, too, but Acronis is very good.