Stepmania 5 working on its own?!?!

Exactly that, when i open the programme it works on its own, randomly selecting stuff but not actually play. I've tried reinstalling, updating, serveral times. This is on windows 8 and I havent had the problem until recently. It happened after putting some songs in, but they dont seem to be the cause cos i deleted them and its still screwed.1.1.1

You have turned on Monkey Input on accident. Hold F3 and tap 5 to turn it back off.
You'll see a list of other debug stuff too. The normal state is for Slow, Halt, Lights Debug, Monkey Input, and Rendering Stats to be off, Vsync and Multitexture depend on preferences set in the graphics options, and the other things in the list are actions you probably don't want to use.

Thanks a plenty, that seems like a useless feature tbh

It's useful for devs testing whether someone pressing random stuff will crash the game.