Micro 8051

How can you store the string that comes from the visual basic in the buffer then display it in the LCD screen?

You have not given us much to go on, but the characters are transfered from the data memory of the 8051 to the data memory of the LCD display controller (probably a Hitachi 44780). After they are moved to the LCD display controller they are displayed repeatedly until they are changed.

If you need a more specific answer the then you really need to formulate a better question.