ONE QUESTION NOW THOUGH.......strange thing

i am trying to copy the "=vlookup(A2,po,2,fasle) down to the last active row BUT it appears to only returns the value of the active cell that i copy form EVEN THOUGH the formula in a few rows down appears to be correct.

for example, the results for the vlookup in row2 is 18987. then i drag this formula to the last row (R180). all of the cells from row 3 to row 180 return a value of 18987 BUT THE FORMULAS are correct...........that is "=vlookup(A3,po,2,false)" for row3,"=vlookup(A4,po,2,false)" for row4,"=vlookup(A5,po,2,false)" for row5, etc.

any ideas?