Firstly, if you have a new PC, you will have to reinstall windows - you cannot simply copy it across from the old PC. Different motherboards have different drivers and extras and a new installation is the only safe way to ensure that your new PC will work correctly. This will mean that you will also need to re-install most of your software, but we'll come to that in a moment,
I would recommend that you set up your old HD on the new PC as slave, and get a partition manager rather than try using FDISK. I always use Partition Magic but many prefer the various freebies that are around - that's up to you.
Now create a new C:\ partition of about 2 GB and use this just for your OS and leave the rest as an extended, partition. You can, at the same time, copy your old HD to a space on the new HD. Now install WIndows and all your H/W drivers to the new C:\ partition, and reinstall all your software over the top into the created D:\ drive - this will protect all your settings whilst setting up your windows registty to work with the software. You can also copy any settings files only form your old Windows installation before deleting the Windows folder from the D:\ drive. You should now have a working system on C:\ and all the rest of your old system on D:\. Whilst you're about it, I recommend creating a separate drive to store all your data files (much easier to back up an entire drive - and you might want to consider taking a copy of C:\ and storing it down the other end of your drive. Then if your original becomes corrupt, its a matter of seconds getting back up and running again.