yes I realize that now so sorry! And yeas I meant click box not check box. I am the recipient of the project that used the imported PPT files. And have to add some things to it.

As I wrote before: the click boxes were added so that the Captivate project acts like the PPT, you have to click on the slide to advance to the next slide. Do not add an extra button, which moreover has a pausing point which is left at 1,5secs, which means that the whole slide has not yet played when it is paused;-; here is a link to one of my recent blog posts about pausing timelines:
Pausing Captivate's Timeline - Captivate blog
Look at the timelines: you'll see that the click box only appears later and is pausing right at the end of the slide as it should be. Take out those buttons, please.
I have no idea why that click box is missing on a slide: you have to check the Source PPT file in that case.
What do you have to add? Each PPT slide is turned into a movie slide, nothing much can be edited nor changed. Captivate is not a PPT-converter, it is a full-blown eLearning authoring tool. Starting from a converted PPT-file will limit its functionality tremendously.