Okay, so for some reason when I go to try and play the game I press the enter it acts like the down arrow and I go to try and press any other key, but they don't work either. I have tried uninstalling then re-installing the game completely and installing a different version of the game, but the same result happens each time. I'm unsure of what to do at this point given I've done all I personally can to solve said issue, only to be no closer to solving it.
Sound like a problem with the key mappings. Settings are stored in locations that can persist through a reinstall. Try to clean up any stepmania data in the locations mentioned on the wiki, and see if the key mappings are back to normal.

Would this include StepMania songs as well? I have a bunch of those downloaded with the game and I tried looking through my system for what the wiki mentioned, but couldn't find anything.
If it's a key binding problem, Keymaps.ini is the only one that needs to be cleaned up.
< cybik> til Kyzentun fixes bugs for breakfast
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< maxvg1> shakesoda: then why do i still play lol
<@shakesoda> because you're an ITG player. And thus, a masochist
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<@shakesoda> Kyzentun: I think you might need to put down the meshes for a bit
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< maxvg1> shakesoda: then why do i still play lol
<@shakesoda> because you're an ITG player. And thus, a masochist
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<@shakesoda> Kyzentun: I think you might need to put down the meshes for a bit