I have Windows 10 Professional (x64) Version 1511 (build 10586.420) installed after an upgrade from Windows 7 Pro...
Some things, like loosing my Spider Solitare and having a schizophrenic window system are not to my liking but things look like the OS is working on my hardware.
Mind you, HP not supporting Windows 10 on my z210 workstation may mean i go back to Windows 7 Pro after some more testing...
Anyway, i uninstalled my old version of Kodi from within Control Panel - Programs and Features of Windows 10.
The uninstall process required permission to delete the profile folder but i also looked for and cleaned up any Kodi remnants within the file system (found a leftover shortcut)
I then reinstalled Kodi 17.0-Alpha2 Git:20160229-0ecc4b5 and installed confluence skin which i'm used to using.
Then i added my test library and all works without issue
So i again uninstalled Kodi as above.
I then reinstalled Kodi 16.1 Git:201060424-c327c53 which uses confluence as default skin so not skin update was needed.
When adding my test library, Kodi took some "l o n g" pauses but this sorted itself out once the add video source popup, well poped up.
Kodi worked without issue after this.
Maybe some Windows 10 hickup occured but who knows why, the Windows Logs don't give any hints
So maybe you need to consider that Windows 10 is not working as it should on your Dell Optiplex 380.
In fact, Dell is not testing or developing Windows 10 drivers for this product, so if you choose to upgrade, some features, applications, and connected devices may not work as expected (according to Dell).
No doubt releasing Win10 drivers for the 380 is not difficult but OEMs want us all on that upgrade treadmill :?
The end result is that the onus is on you to verify all hardware dand their drivers are compatible with Windows 10.
Bottom line is that you need to ensure all OS components function without issue on your Optiplex 380, or if that's too much, buy a certified Windows 10 machine.
So check your device manager and fix any issues, look at your Windows log and fix any issues.
Or try a clean Windows 10 install rather than an upgrade from windows 7 (but still check device manager and windows logs post install).