It is possible the laser eye needs a cleaning, calibration and alignment. It is hard to say though because it is a modded 50001. That particular model has a chip that commonly goes out on the board(LA6508), even on none modded systems. The chip can be replaced, but has a high fail rate.
You can send the system to us so we can properly diagnose it:
http://www.videogamerepair.com/FormPage1.htm
Or you can try adjusting/cleaning the lens yourself, but I would recommend you have this guide to do so:
http://www.powerfulguides.com/portal/affclicks.php?pid=VGR
Hope I could be of some help.
Good luck!