这个问题貌似是 SP3 的一个 BUG，请看该贴：http://bbs.pcbeta.com/thread-285640-1-1.html

　　把下面的内容复制到记事本，另存为.reg文件，双击导入即可。

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\inifile\shell\open\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,00,53,00,79,00,73,00,\
    74,00,65,00,6d,00,33,00,32,00,5c,00,4e,00,4f,00,54,\
    00,45,00,50,00,41,00,44,00,2e,00,45,00,58,00,45,00,\
    20,00,25,00,31,00,00,00

[HKEY_CLASSES_ROOT\txtfile\shell\open\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,00,53,00,79,00,73,00,\
    74,00,65,00,6d,00,33,00,32,00,5c,00,4e,00,4f,00,54,\
    00,45,00,50,00,41,00,44,00,2e,00,45,00,58,00,45,00,\
    20,00,25,00,31,00,00,00