I assume for now C,F, and G are one physical drive with Logical drive partitions. When I upgraded my 4 years old PC I had a 500Gb dive with XP Pro installed on the C dive and data on E, F, and G. I got a 2 TB drive and installed Win 7 64 on a 200 Gb partition. With both drives hooked up the primary boot recognized I had two systems and asked whether I wanted to boot under Windows 7 or Previous Version (XP).
This worked well because I still needed to use XP for old DOS programs and Pagemaker which wouldn't run on 7. So I have a dual boot system. The only precaution is that under Win7 your drive naming will change. For example since under Win7 the primary drive is C, the XP bootable drive became D. It is a good idea in such cases to use names for your drives so they are easier to identify. For example I named the Win7 C drive SCOTTY_64 and the XP drive SCOTTY_XP, so that regardless of whether I booted under XP or Win7, I could avoid making mistakes by trying to put files or programs on a drive they could not or should not be installed on. When booting under XP, the SCOTTY_XP drive was drive C.
It can become messy since both OS's and drives will want to create their own D, E, F, G, H etc drives, so it is important IMO to always name your drives in a manner consistent with the type on information stored such as AUDIO or VIDEO or DOCUMENTS, and in my case I added "_1" to indicate they where on the old 500 Gb drive, versus the new 2T drive. Since I had bootable programs on the XP D drive I had to ensure I didn't go on that drive and makes changes that would affect the XP installed programs. This is all just good housekeeping and organization. It is not difficult, you just have to use your head.
If your plan is to eliminate the old OS and only use Win7, connecting the old drive will automatically get it recognized. If need be examine each drive carefully and rename it if only temporarily so you know what it is. Organize your new drive. Copy from the old HD to the new HD all data files (no installed programs) although ZIPS and original installation files are also just data, so if you have a directory or programs downloaded digitally, then by all means save those onto your new HD. Once all data has been moved, you can reformat the old HD if that is what you wanted and make it one large data drive or partition it to your likes.
Be carefull about data saved by programs on the old drive you might not want to loose, as many programs save data in a particular default location, and you might have to search these out to ensure you save the data. If you are not worried about any of that, then you can just zap the old HD.
I trust this will help you. Just plugging the drive in and booting the system with both drives is all that is necessary and see what shows up on screen, and go from there.