A lot of this is Windows bloating up a certain subfolder under the Windows folder.I've had Win7 boxes with 80gb drives pretty much self-distruct over time due to limited drive space, even on limited use hardware such as digital signage or kiosk operations.
I’m typing on an Apple device so I can’t refresh my memory as to what it’s called but it starts with Win.
I asked an expert whether this folder could be deleted and, of course, you can’t touch it. At a rate of 5-15GB per year, more or less, it’s easy to see how a drive can get filled up with this pollution. Thinking a thorough wipe and fresh OS install would get one the space back at the expense of having to redo everything else. Wouldn’t think a cloning program could solve this.
Having a separate drive for your data would postpone the inevitable and not take your data with it when it TUs.