Running out of storage???

I saw a similar question posted a while ago with no workable fixes suggested, so I'll try again.

Image attached of what I seen when I go to my partition manager and click on the "C" drive. I've highlighted everything and right clicked properties to see how much room is being taken by what resides on that drive: 43.7 GB. The attached images of the Partition Manager shows "C" is occupied by 221 GB of something, while the aforementioned shows the actual is less than 25% of that. In the mean time, my computer runs slower than dirt and I keep getting notice I need to clean up disc space. Seriously?

Can someone at Dell help me figure this out. I steered away from your computers for a decade due to reliability problems then finally bought this computer last year, only to be stuck with this.