This is a public service announcement that by installing Office 2003 SP3, the ability to open and save older legacy file formats will be blocked. The reason for this decision is strictly for security reasons. Some older file formats including some from Microsoft are insecure and do not satisfy new attack vectors that hackers can use to execute malicious code. The decision to block the formats is strictly to protect your machine from being compromised.
If you need instructions to re-enable certain file formats, please read this article KB 938810. It involves registry modifications so, as usual, backup your registry before altering.
I would personally convert your documents to OpenXML by using the Office Compatibilty Pack for Office XP,2000,2003. If you need to batch convert ALL of your files to the new format, Microsoft provides an easy to use command-line tool for IT administrators called Office Migration Planning Manager (OMPM). Here is my earlier blog post referencing OMPM. OMPM is great because if doesn't overwrite the original files at all, it simply makes a copy of the file in the new file format so there is no risk!
The following table contains the DWORD names and the corresponding file formats that are blocked by using the FileOpenBlock subkey.
.wk1, .wk4, .wj3, wk1 FMT, .wks, .wk3, wk3 FM3, .wj2, .wq1, .fm3, .wj1
This policy will prevent the saving of files that are older than PowerPoint 97 and that have file formats such as .ppt, .pot, .pps, and .ppa.
All Word files that have an nFib value that is less than the minimum nFib value as set by an administrator
The following table contains the DWORD names and the corresponding file formats that are blocked by using the FileSaveBlock subkey.
This policy prevents PowerPoint presentations that are in a format that is older than the Microsoft PowerPoint 97 file format from being opened. These presentations are saved by using file formats such as .ppt, .pot, .pps, and .ppa.
To enable these file formats, use one of the following methods.
*UPDATE* Read my follow-up article detailing some of the finer criticisms in this post.
Office Migration Planning Manager (OMPM) - download link for tools
*updated* - documentation link on download page is broken. Use link below for guide.
Office Migration Planning Manager (OMPM) - Documentation