do you mean just the denaturation and annealing step was repeated or the whole process with cycling was duplicated? Doubling the denaturation step only will probably not make any difference because DNA and primers are very stable but you need to specify what enzyme is being used and what cycling parameters for people to give an accurate assessment
If this is a regular PCR reaction, Denaturation 2 times in a row before the extension stage won't make much difference.
What do you mean by "random" primers? If you accidentally mixed you DNA sample with wrong primers. A PCR cleanup can easily get rid of small primers. If the random primer does not form FALSE Priming with the template or the false priming is very unstable at the annealing temperature. Then no extension/amplification will happen.
Sounds like you just need to toss out your reactions and start over.
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