drive C has only 24.4 gb capacity but i am losing space very quickly it is now down to 500kb what can i do
Disk Cleanup like CCleaner
to wipe away all the temp files, recycle bins, cache stuff etc... Have a small OS installed. Linux isn't that big. Uninstall windows games, and unnecessary programs.
My number 1 suggestion is to get a bigger hard drive. 24.4 GB is extremely small and if you're running any version of windows, you're out of luck.