网上关于XP 打开方式->选择程序出现错误的情况解决方法：
写一个*.reg文件导入：
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT/Unknown]
"AlwaysShowExt"=""
"QueryClassStore"=""
[HKEY_CLASSES_ROOT/Unknown/shell]
@="openas"
[HKEY_CLASSES_ROOT/Unknown/shell/openas]
[HKEY_CLASSES_ROOT/Unknown/shell/openas/command]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,72,00,75,00,
6e,00,64,00,6c,00,6c,00,33,00,32,00,2e,00,65,00,78,00,65,00,20,00,25,00,53,
00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,00,5c,00,73,00,
79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,73,00,68,00,65,00,6c,00,6c,
00,33,00,32,00,2e,00,64,00,6c,00,6c,00,2c,00,4f,00,70,00,65,00,6e,00,41,00,
73,00,5f,00,52,00,75,00,6e,00,44,00,4c,00,4c,00,20,00,25,00,31,00,00,00
但在Win2000无用，我的解决方法：
[HKEY_CLASSES_ROOT/Unknown]
建立字符串值：AlwaysShowExt
QueryClassStore
[HKEY_CLASSES_ROOT/Unknown/shell]
默认：openas
[HKEY_CLASSES_ROOT/Unknown/shell/openas/command]
默认：%SystemRoot%/system32/rundll32.exe %SystemRoot%/system32/shell32.dll,OpenAs_RunDLL %1
以上为Win2000的“打开方式”出错的键值修改，有时如果这样无效，可将%SystemRoot%直接写成C:/Winnt/ 。
如果WinXP只要将[HKEY_CLASSES_ROOT/Unknown/shell/openas/command]
默认：%SystemRoot
其他不变
另外删除打开方式列表的方法：
打开注册表编辑器，在[HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts]和[HKEY_CLASSES_ROOT＼SystemFileAssociations]分支下中找到相应扩展名分支，然后在“OpenWithList”项中删除不需要的键值或项即可。