If i am reading that correctly, you have copied a 100gb parition onto a 160gb drive, thus you can see your 100gb partition and the 60gb is simply free space which is no use to anyone.
Right Click on my computer, then manage, then disk management this will show you what is going on with your hard drive (in a simple way re partitions).
You want to stretch your current partition or create another after it, windows can creat another but if you want to stretch your current partition something like patition magic or similar will do the trick (and not lose your data) - always backup, always
I hope this helps
Matt
PCT-IT Engineer, NHS UK