I deleted a program I need...just don't know which program it was

I occasionally play games on my computer. I usually download them for free for an hour. I was going through my programs the other day trying to clear a bunch of old programs off my computer when by accident, I deleted a program I need to play DVD's on my computer. I'm not sure what program it was exactly. I only know that before I was able to watch DVD's on my computer but now I can't. The disc drive still reads other discs, just doesn't play movies. I have Windows Media Player so that can't be it. I tried to use system restore but I can't get it to go back as far as I need. Can anyone figure out what program you need to view DVD's?

Wow...there's so many, it's hard to say. They're often a plug-in to a general media player such as Windows Media Player, but not always.
Wish I could offer more help...

Go through your Add and Remove Programs and see if there's a program named "something DVD", or "DVD something-or-another", or "something DVD player". Once you find it, write down the name, and then hit Uninstall. If it errors out saying the program or program group does not exist, then that was the one you deleted.

Google "free DVD player software", and you'll find plenty of free programs that will do the job. You'll just have to download the program setup file, then click on it to install. I can't vouch for a particular one of the free programs on offer, never having used any of them, but I imagine most will work well enough. And if one is rubbish, you can just uninstall it and try another.

You could always download VLC for free. It's the best movie player out there IMHO.

You can get it here for free - http://www.videolan.org/vlc/