If Manmohan Singh falls, heavens will not fall. He is the most weakest PM India ever had. He has no charaisma, the prices of essential commodities shot up during his time and coalition government is not visible. Guided by inexperienced and whimsical Sonia Gandhi, the UPA Government is governing the country for name sake. Don't worry as to who will be the next. The NDA which gave the country a five term coalition with Atal Vajpayee is certainly a better choice than these colourless personalities.
Regarding CPM's intention to move against DMK ministers, I think this is laudable and they should no more be paper tigers or barking dogs. Let's see what happens