Unable to view a PPT file in slide show

I am un able to view a Windows Power Point file in slide show mode. When I click on Slide show button, a new task pops up in bottom showing it as Powerpoint Slide Show. But the slide show does not start. I am using MS Office-2000-SR-1 (9.0.3821). My OS is Windows XP. Is it a virus related?
I un-installed and re-installed Office. Still it does not works.