Office 365 Downloadable Icons

I'd suggest to create also the registry file for change to old ones.
example of the reg file:

Windows Registry Editor Version 5.00

; --- Microsoft Word ---

[HKEY_CLASSES_ROOT\Word.Document.8\DefaultIcon]
@="C:\\_\\msicons\\Word.ico"

[HKEY_CLASSES_ROOT\Word.DocumentMacroEnabled.12\DefaultIcon]
@="C:\\_\\msicons\\Word.ico"

[HKEY_CLASSES_ROOT\Word.Template.8\DefaultIcon]
@="C:\\_\\msicons\\Word.ico"

[HKEY_CLASSES_ROOT\Word.Template.12\DefaultIcon]
@="C:\\_\\msicons\\Word.ico"

; --- Microsoft PowerPoint ---

[HKEY_CLASSES_ROOT\PowerPoint.Show.12\DefaultIcon]
@="C:\\_\\msicons\\PowerPoint.ico"

[HKEY_CLASSES_ROOT\PowerPoint.Show.8\DefaultIcon]
@="C:\\_\\msicons\\PowerPoint.ico"

[HKEY_CLASSES_ROOT\PowerPoint.SlideShow.8\DefaultIcon]
@="C:\\_\\msicons\\PowerPoint.ico"

[HKEY_CLASSES_ROOT\Excel.Sheet.8\DefaultIcon]
@="C:\\_\\msicons\\Excel.ico"

[HKEY_CLASSES_ROOT\Excel.CSV\DefaultIcon]
@="C:\\_\\msicons\\Excel.ico"