The threshold and growth rate of absolute two-plasmon decay instability in a laser-produced plasma, using the fluid theory, for a normally incident laser light, are reported. By taking into account the collisional damping of electron plasma waves and considering a perturbation to the Schrodinger potential, results on the minimum threshold conditions and the growth rate have been obtained and compared with those reported in earlier works. It is observed that consideration of the perturbation to the potential and plasmon damping significantly modifies the threshold conditions, the unstable spectrum of the perpendicular plasmon wavenumber and the plasmon growth rate.