I am very new to Linux. I had a windows10 on my 256 SSD C drive and a few months ago I decided to have a Linux Ubuntu operating system along with my Windows. I followed several instructions in google for adding Linux along with windows and I allocated about 45GB to Ubuntu, but after a while I just deleted that operating system. Now it seems that there is no Ubuntu partition in my system as shown in the following figures, but unfortunately the allocated space is not freed yet and the free space of my C drive is 75GB instead of 120GB. I searched the internet a lot but I couldn't find a solution that could solve my problem. Does anyone have a solution to fix this problem and get back my lost space?
[Edit] The size of whole hidden and non hidden files in my C drive are about 120GB. The sum of my free space (75GB) and used space (120GB) in that drive is 195GB. Finally, the difference between whole space of my SSD drive (237GB) and that 195GB is 42GB which is the lost space I am looking for. I am sure that lost space is exactly the same space allocated to Ubuntu which is not freed after removing that OS. Before Ubuntu installation, I had that space but after Ubuntu removal, it is not back to my free space of C drive.
