Not really. Dark matter makes up so much more of the Universe (~25% dark matter vs. 5% baryons -- stars themselves are closer to .2%) in that even doubling the

Not really. Dark matter makes up so much more of the Universe (~25% dark matter vs. 5% baryons -- stars themselves are closer to .2%) in that even doubling the number of stars would not appreciably change the amount of missing mass. Moreover, dark matter has a different signature on the CMB than ordinary matter does, so you cannot solve the dark matter problem by adding ordinary matter---dark matter has to be something fundamentally different. There is, however, a problem called the "missing baryons problem." Measurements of the CMB predicts a certain amount of ordinary matter in the universe, but the amount of matter observed is too small by a factor of about 2. It is possible that these stars could contribute to the missing matter in this problems. (It probably would not be the stars directly, but a tenuous gas from which the stars formed.)