Upgrading a Latitude D620 processor

I just bought a new processor for my latitude, the Solo core was just too slow. At the time, I was told that I could get phone support to change it out. But when I called for it, they told me I couldn't get it, to get a Dell certified tech which having already spent $500, I don't have. They then said the directions were on the website but I am not finding them. Can someone point me to directions? Any words of wisdom?

Thanks!