I'd agree Windows could be using about 100GB so you haven't much spare without adding a new drive for storage. I run a free utility called 'get folder size' will analyse your drives and you can see what looks unexpectedly high.
With mine I find Adobe is always making cached copies of any video I edit which is supposed to make things run faster. That's all very well but things you won't need again need manually deleting periodically or it takes up several GB. Just emptying the recycle bin will often free up a lot of space |