Ok it doesn't look like I will be able to revive my old system long enough to retrieve the save data onto the new system. At the very least, I managed to get the disc struck inside back - Yakuza 4 which I have yet to complete at that time. I have been grinding the game to about 80 hours plus when my old system failed leaving the story unresolved just before the conclusion.
Once I realised I have to start all over again from scratch, I decided to jump straight to Hard mode and skip the side mission, focus on finishing the story. This is sort of uncharted territory for myself because when I finish the Hard mode for part 3, I had the luxury of using the leveled up characters from my Normal mode save. I guess I wanted the extra challenge when playing the game again since I already played the entire game up till the last boss encounter.
So one weekend of nothing about Yakuza 4 later, I have finish the story mode on Hard mode in a new save file. I remember having a harder time on part 3 even with a leveled up Kiryu perhaps part 4 has a lower difficulty curve as Sega was incorporating three new characters into the fray.
