king of fighters glitch-problem???

[totoro]

Hello everybody!!!

I just sold a king of fighters 2000 which i had bought a month ago ...

The buyer claims that at the prologue/intro video
lines and squares appear but not while playing the game.

What is this supposed to mean?Is it a damaged cart??What is wrong?
Any help would be very much appreciated!

Thank you!!

 

[Late]

Probably just dirty contacts.

The game was fine before, right?

 

[totoro]

yes i played two -three hours max and i did not like it so i decided to sell it...The game was fine
What should i tell him to do ?How to clean them??