Besides being dishonest, it shouldn't harm your computer any more than sitting at the keyboard and constantly pressing F5 would.
Your PC might be caching the page, reducing bandwidth, or it might not. (Certainly some things are being cached). At any rate, it would be using some bandwidth, though a negligible amount.
If this is on youtube, and you're attempting to get money from views, youtube checks to see if the views are 'valid'. I have no idea how they do that, but considering they are owned by Google, I'm sure that what ever their process is, it works.