ок, давайте начнем с файлов doc и docx
Примените этот твик реестра:
Код:

Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.doc]
"Content Type"="application/msword"
@="Word.Document.8"
[HKEY_CLASSES_ROOT\.doc\PersistentHandler]
@="{98DE59A0-D175-11CD-A7BD-00006B827D94}"
[HKEY_CLASSES_ROOT\.doc\shellex]
[HKEY_CLASSES_ROOT\.doc\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}"
[HKEY_CLASSES_ROOT\.doc\Word.Document.8]
[HKEY_CLASSES_ROOT\.doc\Word.Document.8\ShellNew]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc]
"Content Type"="application/msword"
@="Word.Document.8"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc\PersistentHandler]
@="{98DE59A0-D175-11CD-A7BD-00006B827D94}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc\shellex]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc\Word.Document.8]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.doc\Word.Document.8\ShellNew]
[HKEY_CLASSES_ROOT\.docx]
"Content Type"="application/vnd.openxmlformats-officedocument.wordprocessingml.document"
@="Word.Document.12"
"PerceivedType"="document"
[HKEY_CLASSES_ROOT\.docx\PersistentHandler]
@="{D3B41FA1-01E3-49AF-AA25-1D0D824275AE}"
[HKEY_CLASSES_ROOT\.docx\ShellEx]
[HKEY_CLASSES_ROOT\.docx\ShellEx\PropertyHandler]
@="{993BE281-6695-4BA5-8A2A-7AACBFAAB69E}"
[HKEY_CLASSES_ROOT\.docx\ShellEx\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}"
[HKEY_CLASSES_ROOT\.docx\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{C41662BB-1FA0-4CE0-8DC5-9B7F8279FF97}"
[HKEY_CLASSES_ROOT\.docx\Word.Document.12]
[HKEY_CLASSES_ROOT\.docx\Word.Document.12\ShellNew]
"NullFile"=""
[HKEY_CLASSES_ROOT\Word.Document]
@="Microsoft Office Word Document"
[HKEY_CLASSES_ROOT\Word.Document\CLSID]
@="{F4754C9B-64F5-4B40-8AF4-679732AC0607}"
[HKEY_CLASSES_ROOT\Word.Document\CurVer]
@="Word.Document.12"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx]
"Content Type"="application/vnd.openxmlformats-officedocument.wordprocessingml.document"
@="Word.Document.12"
"PerceivedType"="document"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\PersistentHandler]
@="{D3B41FA1-01E3-49AF-AA25-1D0D824275AE}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\ShellEx]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\ShellEx\PropertyHandler]
@="{993BE281-6695-4BA5-8A2A-7AACBFAAB69E}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\ShellEx\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{C41662BB-1FA0-4CE0-8DC5-9B7F8279FF97}"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\Word.Document.12]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.docx\Word.Document.12\ShellNew]
"NullFile"=""
Готовый reg файл