All document types relevant to Office 2007 can be converted.
When using Office 2007, you can be prompted under certain circumstances to convert the existing file into the new Office 2007 format (OOXML).
Once you confirm, the document has the new Office 2007 format.
Activate password protection for a Word2003-document under Office 2007.
Result: The doc-file becomes a docx-file.
Activate password protection for a csv-file (comma-separated text file) under Office 2007.
Result: The csv-file becomes an xlsx-file.
This test is made for all types of files which are linked with the Office 2007 applications (Word, Excel or Power Point) (automatically opened via click).
The user-specific configuration of the linking between type of file and application to be executed is taken into consideration here.
The configuration of the linking between type of file and application to be executed can be opened in Windows XP through Explorer - menu Extras/Directory options - tabType of file.