I have a game that used to work but now shows garbage on the screen. Sometimes it plays blind,sometimes not. Also the sound effects are present but no music plays. I know the boardset is perfectly fine. Could this be a PS issue?
Yes. It is very possible. If you a have a switching power supply, check the voltages at the board. You may just need to adjust the +5V. Switchers tend to driuft a little over time.