I wouldn't think of DVDs as "software" that you "install" like any other software. DVDs are optical storage media for files stored in a specially encrypted format.
I'm not sure if you are trying to copy files or just play them. Extracting and decrypting files from most commercial movie DVDs is borderline illegal in most countries.
To simply play a DVD, all you need is DVD player software. I don't know the best software to do this. However, the two that I use are:
VLC Player
Media Player Classic or MPC
VLC Player includes DVD codecs, I believe. I've not personally used the latest version of MPC, but still use an old classic version.
If you purchased an original IBM-supplied DVD drive for a 600X, then it shipped with a DVD player called Mediamatics DVDExpress. That software player is generally regarded as an inferior DVD player, but some people (including me) consider it abandonware, so you can obtain a copy of it here:
http://thinkpads.kiff.ca/files/DVDExpress-27L2581.ISO
Some versions of DVDExpress were specifically customized for Thinkpads, including the 600 and 770 series. If you decide to install DVDExpress, then you will want to use the ISO above to install it, and then immediately update it to the latest version available from IBM:
http://www-307.ibm.com/pc/support/site. ... IGR-4GV37K
The update is a full release that completely replaces the version installed using the ISO. The only reason you need to use the ISO release, is that the update requires that you already have DVDExpress installed in order to perform the update install.
I usually have all three of these programs on my 600 series machines (DVDExpress, MPC, and VLC Player). And they can all happily co-exist on the same machine with Windows Media Player. If you install DVDExpress, then it will also install DVD codecs for you. Those same codecs will then allow you to play DVDs with your built-in Microsoft Windows Media Player. And then you can use whichever one you like, or you can try another one if you run into problems with any particular file.
DVDExpress is the weakest of the bunch, and it can leave a bit of a mess behind in your registry and in your system folders that it doesn't necessarily clean out as well as it should after you uninstall it. The others are very well behaved.
Phil.