C drive getting full in windows 10 for no reason

I had 37 GB free on my main OS drive (C:) in my 512 GB SSD hard-drive. I installed a 2nd 1 TB drive anticipating needing more disk space soon. Just in few days c:\ drive got full for no apparent reason. Only thing I did was updated visual studio (which I do regularly so shouldn't be that big).

I moved stuff from c:\ to the new d:\drive and uninstalled some unused apps too to free 30+ GB disk space.

Now my c:\ drive is again full with no updates that I have performed and no new software installed. I have hardly even used the PC during this time but my PC is always on.

So why is my disk getting full? How do I know what's happening?

Update

I installed/ran WinDirStat as suggested in comments here is the top folder sizes.

My Program Files folder is too big!

Further opening the Program files, MS SQL Server is literally taking all of the space! And digging further, its the log files it creates!

I don't even use SQL Server, I only installed it with Visual Studio and plan on learning but nothing yet.

So given that, do I need reconfigure SQL Server or uninstall it? The log files are crazy.

So my problem was SQL Server whose log folders was taking up all the space and inside that it was the actually the dump folder which was 348 GB large so not exactly the log files. It has growing number .dmp files.

I had installed it (actually couple of times because first it failed) but never really used and don't have any critical data. There are signs the installation is wrong as I have two similar looking folders. Cleaning up and installing correctly should fix it.