AES Memory Card Problem

I recently purchased a used NeoGeo AES system and memory card from Japan. When I access the memory card menu and try to delete some of the old files or even format, it doesn't do anything. The old save files remain and still work on their appropriate games.

Is there something I'm doing wrong? The way I understand the menu is:

1. Format
2. View Files
3. Copy
4. Delete
5. Owner Info
6. Exit

Right?

BTW, I'm trying to make a spot for a US. Metal Slug 4 file. Is it because the System and memory card are japanese and the game is US.

Any advice is greatly appreicated. Thanks in advance.

I had the same Problem,how i can I save on Ms4 ,when the question on the end comes,an i will save,there only comes Japanese Languages..

anyone an idea?