Hi Shameer

As far as I know there is no shortcut for the highlighter pen (all shortcuts
can be seen by using F1 during a presentation). Quickest way to get it is to
have 'Show pop-up toolbar' enabled (tools->options->view) then click on the
pen icon and select highlighter.

As for annotation not showing up, I read this in a previous post from John
Wilson:

Try this (even though it might sound unlikely at first!)

With Powerpoint closed! Right click the desktop
properties>settings>advanced>troubleshoot (note ignore the first
"troubleshoot" you see)

Slide the Hardware acceleration slider to the left. OK out and open powerpoint

Hope that works for you.

Lucy