You could just download and install RocketTime. You can configure it to automatically check and correct your computer time. You can set it anywhere from 1 hour to one a week. I use this on several computers, even servers, that I want to keep accurate time on. I also use it on a K7S5A board that doesn't keep good time (strays by a couple seconds or minutes a day.)
There are many programs that do this, but I have found that many of them have spyware in them. I like RocketTime, because it's free and spyware free.