[ottoman]

Definitely a media or laser issue.

All the chip does is boot the game, not keep it running.

I would have said a media issue as well but don't rule out laser problems.

Have just installed a messiah 2 into a v5 ps2 and it wouldn't run ps2 cdr because of laser. version 5 to 7 r meant to have superior lasers but that don't mean they r indestructable.

As advised, go for ritek, dont bother with other brands that use ritek dye cos they ain't as good and some tend to degrade over time. what starts off as a perfect back-up ends up not even boooting after a couple of months.

U could also try running a dvd lens cleaner through the ps2 as it could just be a dusty lens ( stranger things have happened!)

Hope u get it sorted!