We have documents on our network going back many years. Migrating these old files to newer formats hasn't been a big problem, we've always been able do them on an as-needed basis. But we had to open a Word 5.0 document a while back and that required a bit of work to get 2003 to handle it (and only gave us the text, minimal formatting) and it got me to thinking.
I see it as being two related problems:
Opening very old documents just to get the information out. For us, it's mostly a matter of getting the text out, I've never been asked to convert an old 123 file.
Converting old, but not ancient documents to a newer format for easy access. Most of what I consider "old documents" are WP6.1, and Word, Excel, PPT files from Office 95 or 97. These all open in 2003, but we do run into formatting issues. One think I'll be doing soon is testing how well the old docs open in 2007.
I'm considering two main approaches:
Set up some VMs with Windows XP and appropriate versions of software to be able to open old documents. At this point, it would probably only take one VM that could have Office 2003 and WordPerfect Office 6.1.
Are there any good batch tools that will convert older .doc .xls .ppt files to 2007 format? If there are, I'd certainly consider running all the old files through one.
First of all, don't lock your data up on closed-source proprietary formats. The problem starts the day you do that, it just doesn't get noticed until much later.
For archival purposes, think as much ASCII as possible, followed by published and freely available graphical formats. In particular, consider PDF. PDFx is an ISO standard. Adobe it its champion, but the standard is free to use and will be readable for longer than you are!
Good luck. Archiving and recovery) can bring some neat challenges.
PS: Check out the references at the end of this paper for more info.
It may be worth downloading and installing openoffice.org. I have had some success opening up spreadsheets and word docs that MS Office struggled with using oo.org. Using it for PowerPoint has been less successful though.
For the purpose of batch tools to convert older documents to the 2007 format, have a look at the Microsoft Office Migration Planning Manager. This tool will scan your systems and report back on compatibility issues for upgrading to 2007. At the bottom of the page is a converter for Office 97 up to 2007, but I'm not sure about 95 versions or WP6.1. These might take some manual work, but the tool will provide reports and an "inventory" so you have a good starting point. It takes a little bit to set it up, but it worked well for our migration. We did not do the auto convert though, we just forced our users to start saving in the new version and then go back and upgrade their old documents as they had time.