I was trying to open some old documents but got this error
instead:

The document name or path is not valid. Try these
suggestions.
Check the file permissions for the document or drive.
Use the File Open dialog box to locate the document.
C:\...\file path\file name

I've tried all the methods recommended from Microsoft
Knowledge Base Article - 328100 but still could not open
these documents.

Installed Office XP SP3 but problem still persists. I need
some solutions urgently as these are important business
documents.