That really sounds like your video driver. Sounds like Intel?
MAME does have a set of rotate options -rotate rotate the game screen according to the game's orientation needs it -ror rotate screen clockwise 90 degrees -rol rotate screen counterclockwise 90 degrees -autoror automatically rotate screen clockwise 90 degrees if vertical -autorol automatically rotate screen counterclockwise 90 degrees if vertical -flipx flip screen left-right -flipy flip screen upside-down
But it really sounds like your driver is doing something odd. It may be worth snagging 'intel driver update' utility and installing the latest drivers. Win10 does not put in the latest ones just the latest certified drivers for your chipset. Even then they can be out of date.
You can create a config file using the '-createconfig' option. There are a set of rotate options in there. But it probably will not do you much good as they do pretty much the same thing as the command line. Worth a try though.