What the hell does CTRL+Z ACTUALLY do? Animation/render issues?

I have messed around with Blender in the past, but never really enough to have any idea what I was doing, or with any real purpose, so I’m pretty much 100% fresh to Blender. Yesterday, I decided I wanted to design a gaming room in Blender, just for the hell of it. I had a very specific thing in mind, so I got started, and made decent progress learning how to use Blender and all that. However, this morning, when I started modelling the Monitor and adding a screen image, things started to turn to shit. Every time I render, my scene gets reset. I’m pretty sure this has something to do with the animation, but I can’t figure out how to get rid of the animation. On top of that, every time I make a mistake and, out of habit, hit CTRL+Z, expecting it to act like it does in ANY OTHER PROGRAM, it just ends up moving all of my duplicate monitors into one tight space, some of which are split back up into their original pieces, some of which remain as a whole. Can any one explain what the hell CTRL Z actually does? Because it certainly isn’t undo, considering it’s moving things to place I never put them. Any help totally removing all animation from a scene would be awesome too. I’d like to be able to get rid of anything after the first frame.

CtrlZ is undo, CtrlY is redo. Make sure that you are in the mode that you wish to be in when using these keys (object or edit).