The fact is, this time machine that I built is never going to work until I get the super computer running.
Consider: when you travel through time, you stay in one place spatially and just move through years. But it’s not like a tesseract or a jump: you have to move through every second of time that happens in that spot before you get to the moment in time that you are aiming for. Just like you have to move through every inch of space between you and the place you’re walking to. Granted, this move will seem to happen instantaneously, because that is what time travel is all about; nevertheless, you’re passing through all that time. And don’t you think that somewhere in the hundred or thousand or million years you just moved through, someone walked right through where you’re standing? Meaning you are dead as soon as you hit that moment. (This might explain spontaneous combustion: if some time traveler just happened to be where you are for a single instant, what else could you do but explode? Wait, I guess that only explains spontaneous explosion.)
Anyway, the super computer will avoid all this, because it will be able to identify every movement of every atom in the Universe from the theoretical beginning of time right up to the theoretical end. So you will know where to stand when you are time traveling, because it will identify the spots where no one else is standing during the period in question. (But you would be wise to pick a different spot for the return trip.)
So, even though I promised a lot of people rides in the time machine as Christmas presents, I think it would be better to get it as your Groundhog Day present. The computer should be working by then. I just have to hack into the mainframe and download the access codes.