Hi Rhea,

I had a similar problem. None of my manipulators were showing up in Perspective view but somehow they showed up in earlier iterations of the project.

This is what I did that brought them back:

Try going to "Show" -> "Manipulators".

*Even if it's already checked, un-check it and re-check it*

For some odd reason, it worked.

Hopefully this works for you.

P.S.
I've tried the whole "press -/+", "update/re-install video card drivers" solutions and they didn't work - so I'm guessing the problem I had (and this solution) was different than all those other/similar posts.