Hi again GenieKhan.
If you used CCleaner's default settings for deleting temporary files then you have nothing to be concerned about.
What do I mean by default settings? I mean, when you open CCleaner, the first page it opens to is the page that analyses your hard drive's Temporary files, Temporary Internet Files, and other temporary data that is not needed, but which builds up over time. Making no changes to the settings on that page, and then deleting the files that CCleaner marks for deletion makes no difference to the performance of the system.
CCleaner does have other pages/options, eg a registry analyser/cleaner page, but if you are not sure, it is always best to stay away from that. Having said that, CCleaner's Registry cleaning option is quite benign, and having used it myself on occasion I have never had any problems.
You mentioned downloading things through IDM. I'm not sure what IDM is, but I think I understand what you mean. Correct me if what I say below is in error;
Downloading and installing software.
1] You have an 80 GB drive of which 19 GB is the C Drive partition reserved for the Windows installation. You have one or more other partitions on this same hard disk for other things.
2] When you install software you install it to 'another' partition. That means that, when you watch the installation process, if the install offers you to change the default location for the installation, you change that location from C:\Program files\ to some other partition.
3] There is usually no problem with that. Occasionally some software will not offer a change of install location, (Adobe software springs to mind), but if the software does, then Windows is quite happy with installing the software on different partitions.
4] However: However, most software installations will also install files all over the C drive, eg in the C:\Windows folder, or in the Users folders. You cannot prevent that as this is where the installer places those files. So your C drive will continue to fill up as and when you install software. Usually those files are not very large, and makes little difference to the remaining space on the C: partition.
5] Even if you uninstall software installed on other partitions, not all files are deleted. Software developers are notorious in failing to program their uninstaller procedures properly, and while the main program/software files are removed, there will always be remnants left behind.
I hope that helps.