set enabled of cell "cellname" of matrix "matrixName" of drawer "drawerName" of window "main" to true -- or false
but from what you were writing … (just a wild guess) might it be that you didn’t want to enable or disable a cell (turns grey and can’t be clicked when disabled) but setting it’s content (state of button cell) instead?
you can set it like so for example:
set content of cell "cellname" of matrix "matrixName" of drawer "drawerName" of window "main" to true -- or false