Kindly I ask your attention.
Deinstall/Restart System - Install/Restart System.
Or you have a 3TB HDD and the software can't cope with it?
When so, download the Windows 3TB HDD Unlocker. Install it and you can use the whole disk, 3TB.
But it can be that you need to create a new folder/map on C://, give it the name you want it to be.
Than you go back to the Partitioning program and ad the folder/map, than you might be able to ad all the free space to C:.
https://www.google.nl/?gws_rd=ssl#q=Windows+TB+HDD+unlocker+software+download
Put the name of your mainboard or HDD in front of it, might help.
I asume that you have Windows.
Go to Search Programs and type Partitioning, click Partitioning etc.
A new window will open, wait a little while and the program will show you all the HDD's/SSD's that are installed.
Try here to resize the HDD.
Is it the Free version or paid?
Hopefully I let you known enough, that you will find the answers you seek!
Good luck & have fun doing it!
Best Regards,
MeneerWitte