Corrupted Data on PS2 memory card
I don't know if you have been trying to delete the data with a game inside the ps2, but in case you have, try this.
Turn on the system WITHOUT a game inside, select BROWSER,
the MEMORY CARD ICON, and i believe the corrupted data icon is a
grayish black square. Choose options and then delete.
I am also heard that inserting a music cd will work as well, probably just has to not be a game inside the ps2.
Corrupted data comes from turning off the ps2, or
removing the memory card while the game loads or saves data to/from
I really hope that helps, ps2's are meant to be played! Good luck.