You will not find a free slide show that will provide the features you need.
Many years ago I spent most of a year trying to find a slide show program that would provide what I want.
I found one and have been using it for years and have made over 100 slide shows with it,
Including three wedding slide shows.
It is not free ($70).
However, you can download a trial copy that lets you use all the features and see if it can do what you want.
You can find it by doing a Google or Bing search
I've already tried using two different Windows based slide show programs and both are sorely lacking. Typically I'll set up a slide show using my 5 year old PC. I then run the image files over to a large screen HDTV for optimum viewing. At first I got into a rut by always using the XP Slide Show option found in My Pictures. That was okay....for awhile. But then I became disappointed about not being able to set the view time, or alter the view time in any way (the default view time is around 6 seconds - much too fast if the image is photo contest worthy). And I was disappointed that the files always played in alphabetical/numerical order (no shuffle mode, darn it), which over the course of time became a problem.
I then discovered XP's Screen Saver, something I had never had a use for.
When I discovered it I was very surprised to see that you could set the view time for as long as three minutes. That was great for showing images! Even better, it did not play the files in sequential order! But after a week of testing Screen Saver it did not appear to really shuffle the images as good as it should have... all 2,354 of them. That's a lot of images. But even with all of those images there appeared to be a small amount of redundancy built into XP's Screen Saver, which is no good and a bit of a buzz-kill when you're having a slide show in front of friends.
And so now I'm off to buy my first thumb drive, something I'd never done before, since I never had the need for one until now. And that's because I realize I have a PS3 sitting ten feet away from me. I'm a casual gamer, nothing hardcore. I rarely use my PS3. I barely remembered I had a PS3. The 2,354 images I referred to are kept in a folder and are 4 GB's worth of data. I just took a look at PS3's Photo Gallery and it looks as if it has quite a few options for a user to employ, which is very interesting.
I'll find out how good their software is when when I obtain the thumb drive that'll allow me to transfer the images from my computer over to PS3.
Until then I can only hope that the PS3 program offers the user a wider variance of view times to select from so it doesn't always run at one continuous warp speed the way the slide show in My Pictures does. And I hope it has a shuffle mode, which is what it should have if their developers had their heads on straight when they originally drew up the software's blueprint.