Multiple reasons:
What you are looking for is Blackbox for Windows or BBZero.
Until version 3.0 Openbox was a fork of Blackbox.
That's an old classic. A more elaborate variation on this idea was when I built a computer using blackbox for Windows and removed all 'objects' from the desktop, and used black wallpaper with an all black cursor. People would walk up to it with the monitor on, computer running, and see nothing. Left click did nothing. No idea why, but nobody ever tried right clicking - which launches the main menu (think Start menu) from the desktop starting at the current cursor position. Since BB4Win can run 'on top' of Windows as a non-installed file, you can pull this off as a prank with 1 file if you have time to configure it, or 2 if you bring your own config file.
When I was playing with a Pentium I in my parents' basement I experimented with replacing the window manager in Windows 95. My favorite was a Windows clone of the BlackBox WM for XFree86 [TRIGGER WARNING: Sourceforge]. It was super minimal and made me feel like a real hacker. Interestingly, it appears to have lasted significantly longer than the Linux version, though it was still last updated in 2009.
No idea if this will work with Windows 10, but, I use to use it on Vista back in the day, it's like a Linux desktop alternative for Windows. It's called Blackbox. All the geeks out there who know what this is, I'm proud hehe. http://bb4win.sourceforge.net/
I used BlackBox on Windows and it was kinda good, but there were some issues and I find the Windows 10 desktop just fine now.
I didn't try OpenBox too much, but if its same like BlackBox I would have to use mouse a lot and I don't like that. I had icons in Desktop folders and had to a lot of scrolling to launch what I wanted, keyboard is just much faster and simpler.
I like tilling wm, I use i3 everywhere I can and I just launch everything via dmenu, so I just hit win+d start typing name of the command and hit enter, very similar to win key and typing stuff on Windows, but faster.
It is not tiling, but it is technically as close to a different window manager as you can get for windows. I played with SharpE a while back, but didn't like it because it felt like an awkward XFCE. For a period of time, I used bb4win after I fell in love with Openbox, which is a similar utility to SharpE.
Many (if not most) of the best free software apps are available in a portable format, not needing admin rights. PortableApps.com is your friend.
That said, the only thing I always use my admin rights to install on a corporate XP machine is BlackBox, because I can get work done 3x faster on it thanks to keyboard shortcuts and virtual desktops. I wish to hell BB4Win worked reliably on Windows 7.