What version of Filemaker are you using. v13 has options for this that older versions do not have?
IF not using v13, what kind of layout view will you be using? Form, list or table?
The layout view is form, I have found an option to hide if; I input to his if the field is 2 but it doesn't work.
Hide Object When is then the setting to use. It should work just fine.
If you want a button to not be visible when Field1 = "No", then you would use:
YourTable::Field1 = "No" as your hide object when setting provided that field1 is defined to be a text and not a number field and assuming that your value list enters the exact text "No" when that option is selected and not some other values such as a hidden field 1 value or the the text: "No " (extra space). Note that this expression will not hide the button if the field is empty.