Less than half of hard drive usable



Screencap of your Disk Management window, please.
 


http://imgur.com/tx9GN1a
 


OK...you should be able to Extend that C partition into that 69.51GB Unallocated space to the right.
Right click on the C partition. Does it give you that option to Extend?
 


Yes 😀 (sorry about all the hard drive questions recently, I don't know how to troubleshoot them)