I need to programmatically control powerpoint/pdf presentations (the 4 direction keystrokes need to work at the minimum to go to the previous and next slides).
What
You can try PyQt or wxPython
Here is a link for how to handle key press with PyQt - http://www.saltycrane.com/blog/2008/01/how-to-capture-tab-key-press-event-with/
and for wxPython - http://www.wxpython.org/docs/api/wx.KeyEvent-class.html and http://zetcode.com/wxpython/events/