Calculate slowing sheet

[antony moseley]

HI,

If the below formula is activated - e.g. something is put into cell f8 or g8, the I get the word calculate in the bottom left hand size of the s/sheet.

Anyone know how i can over come this?

Thanks

Antony

 =if(and(f8="",g8=""),"",concatenate(left($a$1,2),mid($a$1,4,2),(mid(a8,3,3)*(left($a$1,2)*mid($a$1,4,2)))))