save nul value. but it is not save in same rows....

when i try to save data in other sheet. it is save but, if middle name is null in last record. then after i save other record the data is not save in same row.

i also want "sr.no" come automatically form data..

for.ex.

if in sheet2 last "sr.no" is "7" then it automatically display "sr.no" "8" in sheet1

please help me