I did in fact used Defraggler yesterday and scheduled the boot time defrag but while performing the boot time defrag it crashed and my laptop turned off. When I booted it again I tried defragging using the Windows' default utility and it did it in like 2 hours. After that, I tried shrinking the disk again in computer management, and it showed that around 67 GB can be shrinked which was most welcome to me. So, I started it but after some time it gave me an error that there is not enough free space available to perform this operation. I tried to shrink with even smaller numbers like 60GB or 55GB and even 50GB but to no avail. And that was the end of my adventures.
Defraggler is a popular and free defrag application that has a boot time mode. It is compatible with Windows 8 as per their website and I used it a few times myself. I think there is an option in it to move large files to the end of the drive so make sure that option is not enabled before you start it.
Boot Time Defrag: http://www.piriform....oot-time-defrag
Move large files: http://www.piriform....ions-defrag-tab