文件单击右键，选择打开方式时，提示无关联程序

复制下列语句到记事本，然后把后缀txt改为reg。双击导入注册表。搞定！！希望帮到你！！
内容为：
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

可能是因为重装系统的缘故 重新关联一下就可以了