http://www.ehow.com/how_8174512_remove-file-association-windows-7.html百度快照照下来的。。。Command Prompt- 1Click the "Start" button, type "cmd", and press "Enter" while holding the "Ctrl" and "Shift" buttons. This runs the Command Prompt as an Administrator.
- 2Click "Continue" in the confirmation window. If you are not currently logged in as an administrator, enter the administrator password.
- 3Type "assoc .EXT=" in the Command Prompt window, replacing "EXT" with the actual file extension. Press "Enter" to remove the file association.
Registry Editor- 4Click the "Start" button, type "regedit" and press "Enter" while holding the "Ctrl" and "Shift" keys.
- 5Click "Continue" in the confirmation window, or type the administrator password, if requested.
- 6Navigate to "HKEY_CURRENT_USER\Software\Classes" in the Registry Editor. Right-click the extension under "Classes," select "Delete" and click "Yes" in the confirmation window.
- 7Navigate to "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExt." Right-click the extension under the "FileExt" folder in the left-hand pane, and select "Delete." Click "Yes" in the confirmation window.
- 8Test that the association has been removed by double-clicking it from Windows Explorer. If it opens an associated program, then continue the procedure. If it asks you to choose a program, then the association has been removed.
- 9Hold the "Ctrl" key and press "F" to search the Registry. Enter ".EXT", replacing "EXT" with the actual extension, and press "Enter." Right-click any folder from the right-hand pane that is named after that extension, and delete it. This step may be unnecessary, but some programs place additional entries in randomly named folders.
翻译： 1
打开“开始”菜单，键入“cmd”，按住Ctrl+Shift再按Enter（管理员执行）
2
（可能会有）确认提示，选择yes（有密码输密码）
3
键入“assoc .EXT= ”，EXT代表文件扩展名（注意要保留那个点“.”）按Enter清除文件关联
4
打开“开始”菜单，键入“regedit”，按住Ctrl+Shift再按Enter（管理员执行）
5
（可能会有）确认提示，选择yes（有密码输密码）
6
展开到“HKEY_CURRENT_USER\Software\Classes”，在文件夹（左边面板）下面找到（可能存在的）文件扩展名（形如“.ani”）右键，删除，点Yes
7
展开到“HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExt”，在文件夹（左边面板）下面找到（可能存在的）文件扩展名（形如“.ani”）右键，删除，点Yes
8
检查一下文件关联是否被还原：双击若弹出“选择打开方式”，说明操作完成，否则接着做下一步
9
某些程序可能会把文件关联放在不平常的地方，这需要搜索注册表逐个删除：按Ctrl+F，搜索“.EXT”，EXT代表文件扩展名。这回搜索结果会定位到右边面板，右键删除。接下来按F3（找下一个），逐个删除
p.s.
文件关联删掉了，原来图标还会在，这与图标缓存有关。重建图标缓存：
复制以下代码，保存为 .bat
rem 关闭Windows外壳程序explorertaskkill /f /im explorer.exerem 清理系统图标缓存数据库attrib -h -s -r "%userprofile%\AppData\Local\IconCache.db"
del /f "%userprofile%\AppData\Local\IconCache.db"
attrib /s /d -h -s -r "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\*"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_32.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_96.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_102.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_256.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_1024.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_idx.db"
del /f "%userprofile%\AppData\Local\Microsoft\Windows\Explorer\thumbcache_sr.db"rem 重启Windows外壳程序explorerstart explorer
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