I lost near half hard disk space when try to make a dual boot system

Hi,
I tried to make a dual boot system with a Dell XPS 8500 Windows 8 pre-installed desktop computer. After I used GParted to shrink the drive C, it did not behave look like I used to work on an old BIOS PC. Then, I went back to restore the Windows 8 system. Now, the hard drive C has only 1 TB capacity even though diskmanager see drive C has 1.8 TB capacity. Please see below image link on this.


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I would like either to continue to get dual boot work, or to get Windows 8 uses all 1.8 TB hard drive. The problem is that GParted still sees 1.8 TB in a single partition in drive C. I also tried Windows 8 disk shrink function hoping it can increase size after shrink first. Unfortunately, it says the parameter (of the shrinking) is wrong when I try. I read the relative link on UEFI, Secured boot, GPT etc., but I still have no idea, on using what tool to retrieve the lost hard drive space. What can I do to solve this?

Thanks,