How to format the Memory Card?

[monolite]

When running Resident Evil 3.iso it says that Memory Card A is corrupted and needs to be formatted.

Could you help me?

 

[Agozer]

Press A or Start.

 

[monolite]

I don't know how noob this may sound, but... I press "Enter" and "X" keys, which are my "Start" and "A" buttons and yet nothing happens...