Is it just burned games or is it with legit discs as well? If it's with both there's a very good chance that you've got burnt out capacitors in your console; this is a very common issue with the PC Engine Duo apparently. The first half of this video goes over this exact issue in more detail and shows the repair process; https://www.youtube.com/watch?v=zszqex-b48I
If you wanna try following along with your console you'll need a soldering iron, high tin to lead ratio solder, a solder sucker and a steady hand, along with the replacement capacitors.
"I think that the problem with this video is it is highly derivative of many popular bands within the genre. Although when viewed on its own merits, it does have a deeper groove. However what it has in groove, it lacks in originality. One can't help but be reminded of such bands as Pearl Jam, White Zombie, Suicidal Tendencies and other bands that bear the mantle of so called "Alternative Rock". One is even reminded of Lorie Anderson when she wore curlers. Hehehmhm! This video speaks less to the heart and more to the sphincter. In closing, I think Korn would do well to learn more from -"