If Excel does not like commas, that is not a problem of Excel 2010, but due to your regional settings. Most non-English European languages use the semicolon where UK and US uses the comma. When you source formulas from international forums, you may need to adjust the formulas before you can use them in your spreadsheet.
The AND() function has the syntax
AND(*condition1*,*condition2*,[optional condition n])
Each condition will contain a comparison operator like
=
(equal),
<>
(not equal),
<
(Less than),
>
(greater than),
<=
(less than or equal),
>=
(greater than or equal),
A formula starts with a =
sign, but when you nest several functions inside of each other, you do not need to precede the functions with another =
sign. In fact that will result in errors.
You don't need a semicolon at the end of a formula. That's JavaScript or CSS, not Excel.
So, if we can assume that your regional settings use a comma as the decimal delimiter and the semicolon as the list delimiter, then what you need is probably
=IF(AJ8<4,2;"Apple";IF(AND(AJ8>4,1;AJ8<8);"Cherry";IF(AJ8>8,5;"Pineapple";"the value is between 8 and 8,5")))
A system with decimal point and comma as list delimiter would use
=IF(AJ8<4.2,"Apple",IF(AND(AJ8>4.1, AJ8<8),"Cherry",IF(AJ8>8.5,"Pineapple","the value is between 8 and 8.5")))