weird PCR ask for help - (Jan/17/2010 )
Perhaps you can try dilute your PCR products (thursday and friday) and try run the gel again with the old product (monday and tuesday) on gel and see whats happen. For the time being, I can't really think of any possible reason for this situation as this never happen to me before.
have u stored ur samples properly after running the first PCR ???
@nccutudou: were you able to figure out this problem? haha it seems I'm experiencing the same PCR issue as you =(.