Why my c-drive available storage is showing different amounts of free space at different times, Also

[GOD_DEVIL_1813]

When i purchased the laptop the available free storage in my c-drive is 140gb(approx.) out of 207gb,but it is filling up rapidly even i have not downloaded any applications in the c-drive, Also when i open the laptop everyday sometimes it will show some amount of available space, on the next day when i again open it the amount of free space will be decreased and again the next day magically it will be increased this cycle will be repeated everyday either by increasing or decreasing, why what is the problem for this change of available space in c-drive only drastically and why it is filling very fast compared to other drives? Please anybody reply and tell what's the reason behind it and suggest a better solution

[WAWood]

There is no general solution to stop the "C" drive from filling up.

Windows automatically allocates temporary space on the "C" drive for its use.  Appliications allocate space.  Internet Browsers allocate space.  Everyday Windows functions allocate space. 

While some of these clean up after themselves, others do not.

So the available space will go up and down on a daily basis -- that is simply how it gets used.

You can clean out the temporary space on a regular basis by downloading the Wise Disk Cleaner application.  This is a totally free app I use on all my PCs and it will allow you to do clean-up work with relative ease.