PS2 Green LED remains on, system won't turn on
have you tried holding down the reset button to turn off your console. Months before I bought my Ps2 I noticed my friends turning off their PS2's using the switch on the back. When i bought mine , months later i was invited to a friends house and noticed when he turned off his ps2 by holding the reset button down for a few seconds. After playing on their trampoline i went home and tried this reset button thing and it worked. Although i had the fat bulky ps2 this trick also works on slimline models too. This should solve your problem. The switch on the back i later found out was for when you wanted to turn off your ps2 during a thunderstorm.