Mold in sourdough starter
A possible fix is suggested on this page (point 4):
But if you are trying to get your starter started (as it were) rather than trying to salvage an established starter, I suggest that you start anew with a sterilized container. (I use 1qt pyrex measuring cups, and use plastic wrap over the top, kept in place with a rubber band--I like the wide open access for stirring, etc.)
Anyway, I think you might have gotten mold rather than good yeasts from a temperature problem. If you got mold in three days, I'd guess the temp was too high. You should keep it somewhere that's between 60-70 degrees. Different yeasts respond to different temps: as I recall from my Peter Reinhart books, the best lactobacilli like moderate to cool temps.