Hello,
I am compiling 32 power point slide shows into one big presentation.
My problem is that there are over 1400 slides and many of them are
duplicates. My question is: Is there a software or add on that can
delete the duplicates so I don't have to go through and delete them
individually. I want something that will work on Windows 2000
Microsoft PowerPoint XP. Thank you.

Hello medicalmentor,

After searching for an answer, I found a program that will do this for
you. You can download a fully-functional 7-day trial here:
http://www.slidewhere.com If you need it for more than 7 days, it
costs $29.99.

I downloaded the program and tested it to make sure that it worked. I
modifed a PowerPoint with several slides and made some of the slides
duplicate on purpose. The program is not as intuitive as it could be,
so I have included the steps I used to successfully accomplish what
you are trying to do:

1. Installed the program with the default options, but say "no" to the
last question that asked me if you want to import all your PowerPoint
files.
2. Close the wizard.
3. Next click on File --> Import PowerPoint Presentation. 
4. Find the file, and click OK (it takes about a second for each slide). 
5. Next click on the checkmark next to Slides and click the Slides
menu on the left (you should see a listing of all available slides).
6. Click on the Slides menu at the top --> Find Duplicates. In my test
it did a great job of finding the duplicates. You can easily delete
them at this point in the task pane provided. I found "Match by: Title
and Text" worked the best for me.
6. Go down the list on the left side and press Delete duplicates for
each set. By default, it keeps the first and deletes the duplicates
(even if there are many) after that.
7. Click the close button on the bottom left. It will ask if you want
the "pack" the library now. Say yes.
8. You will now notice that the duplicate slides are missing under the
Slides section.
7. To export the file back to a PowerPoint, click on the Carousel menu
at the top, and click New Carousel.
8. Give it a name in the name section, and then click on the Folder
next to the Filename: indicator to choose a directory to save it to.
9. Click on the +/- icon next to Slides: to open up the Carousel
Loader. Click on the first slide and click on the > button to move
that slide over. Once you have done this, you should notice that the >
button is highlighted, and you can continue to add slides quickly by
pressing the Enter key on your keyboard (instead of clicking for each
slide).
10. Click on save, and then click Close.
11. Finally, click on Generate Presentation.

I hope this successfully answers your question! 

All the best,

tisme-ga