I might have misapprehended the situation. If so, please edit the question title.
At some point a directory called f83db84ff30a71d92e has been left in my C:\ folder. It contains a bunch of directories whose names are numbers between 1000 and 3000, a few files and a setup.exe. The setup turns out to be an installer for .NET 4.
I don't like unnecessary folders littering my disk root. Can I delete it?