If you're using an Excel version that is NOT an english one, you should modify Ivan's code a bit.
In the code you'll see this bit of code twice:<pre>Formula1:="TRUE"</pre>Change the TRUE with one of the following options:
1. The literal transaltion to your own language, i.e., in the Spanish version, TRUE is VERDADERO, so the code would be like this:<pre>Formula1:="VERDADERO"</pre>2. The more prefered option, change the code to this:<pre>Formula1:="1"</pre>This will work with any Excel version, english and non-english, because Excel will consider the 1 as TRUE, so we have the same effect.