Dell S300wi, AKA TI DLP projector and black and white spots on the screen
Many posts were put out on this topic having problem with Dell projectors. I too have two of these and one has snow flaks on the screen. Not only Dell does not honor its warranty obligations, they have posted the most nonsense "what to do" on the previous trends that are shameful. Resets and bulb cleanup which fairly sealed by the way have nothing to do with this problem.
I am and EE in design and manufacturing of electronics and member of IEEE where ALL specs and standards for such devices are created for global use and manufacturing. Both TI and Dell are at fault for doing it, knowing of design fault and the problem and yet ignorant. This product is a great candidate for a mass recall via the government agencies and consumer protection advocate groups. A class action lawsuit would defiantly prevail and all end users will have a free repair or exchange.
Needless to say here are few video clips that would tell you what the problem is, how to fix it and how much it would cost. Remember the fix is the same for all DPL projectors and even projection TVs, but I have focused my research for the unit I have. You should seek same info for your brand and model number. The fixing procedure is the SAME for all such devices.