Clock Changes to Random Times

Hello,
My computer's clock has been randomly changing itself for about two months now, and it seems to be happening a lot more often than it was before. At first, I thought it would just blow over, but it never went away. This can happen when I'm watching a video online, playing a video game, or doing homework. Most of the time, when the clock changes, it crashes the program that I was using. For example, I was recently playing Nuclear Throne, a rouge-like game that doesn't always save your progress, and the game crashed to desktop and showed that it was September in 5960 (or close to that), forcing me to start over. This of course could've been much worse but I just want to prevent this from getting in the way of my schoolwork or whatever else.

I'm not sure what to post here to help the solution to be found, but any help is really appreciated.

Forget that last post, I forgot to reconnect a cord connecting the power button to the rest of the computer after I dismantled it. Everything is running smoothly.

My apologies!