Cell to retain a default value when it is cleared/deleted

Hi,

I am currently working on a excel sheet which will be used by a multiple users. My problem is
I want to have a cell say A1, which has a text say "Enter Name". When a user tries to enter his name the cell will chage to the name he enters. Let us assume that the user entered his name "Mani". Now A1 has the value "Mani".
If I delete/clear the value of A1, I want it to retain the value "Enter Name" automatically. Can this be possible?

thanks in advance.