dna left on thermocycler - (Aug/12/2013 )

Will anything happen to DNA I left at 30C, on with a heated lid of 105c? I forgot to add in the mastermix and placed the DNA onto the thermocycler by itself. Will anything have happened to the DNA? 

For short periods, little or nothing. For day long periods, there might be some degradation if there are DNAses present, since the Mg++ and heat are there.  (Actually, perhaps the Mg++ is not there, without the master mix. If your DNA was in TE, then nothing will happen.)

Indeed, for short periods almost nothing will happen.