When I try to open old files, I get "Excel cannot acces (file name). The
document may be Read-only or encrypted."

But they aren't read-only, and I have no idea how to encrypt a file. The
files have unrestricted permission. At this point, I can't even delete them,
although I don't want to do that. They bare completely unaccessible. Same
applies to Word documents.

These files were created in the 1994 version of Excel. I loaded Excel 2003
last year when the problem started.