解决方案：
打开excel，依次选择：工具-选项-常规-设置-忽略其他应用程序的勾去掉。
初步估计是病毒把excel文件的“打开”设置更改了。
如果还不行，可以尝试将下列红字部分复制到记事本内，保存为excel.reg，然后双击添加到注册表。然后再按上述步骤操作。
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXE]
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshell] @="Open"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellNew] @="新建(&N)"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellNewcommand] @=""C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /e /n" "command"=hex(7):26,00,69,00,67,00,41,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 5a,00,58,00,66,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,45,00,58,00,43, 00,45,00,4c,00,46,00,69,00,6c,00,65,00,73,00,3e,00,21,00,44,00,65,00,40,00, 5d,00,56,00,7a,00,28,00,72,00,3d,00,66,00,60,00,31,00,6c,00,66,00,71,00,60, 00,3f,00,52,00,26,00,20,00,2f,00,65,00,20,00,2f,00,6e,00,00,00,00,00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellNewddeexec] @="[new("%1")]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellNewddeexecapplication] @="Excel"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellNewddeexec opic] @="system"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpen] @="打开(&O)"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpencommand] @=""C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /e" "command"=hex(7):26,00,69,00,67,00,41,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 5a,00,58,00,66,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,45,00,58,00,43, 00,45,00,4c,00,46,00,69,00,6c,00,65,00,73,00,3e,00,21,00,44,00,65,00,40,00, 5d,00,56,00,7a,00,28,00,72,00,3d,00,66,00,60,00,31,00,6c,00,66,00,71,00,60, 00,3f,00,52,00,26,00,20,00,2f,00,65,00,00,00,00,00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenddeexec] @="[open("%1")]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenddeexecapplication] @="Excel"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenddeexec opic] @="system"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenAsReadOnly] @="以只读方式打开" "Extended"=""
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenAsReadOnlycommand] @=""C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /h /e" "command"=hex(7):26,00,69,00,67,00,41,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 5a,00,58,00,66,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,45,00,58,00,43, 00,45,00,4c,00,46,00,69,00,6c,00,65,00,73,00,3e,00,21,00,44,00,65,00,40,00, 5d,00,56,00,7a,00,28,00,72,00,3d,00,66,00,60,00,31,00,6c,00,66,00,71,00,60, 00,3f,00,52,00,26,00,20,00,2f,00,68,00,20,00,2f,00,65,00,00,00,00,00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenAsReadOnlyddeexec] @="[open("%1",,,,,,,,,,,,,,1,,1)]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenAsReadOnlyddeexecapplication] @="Excel"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellOpenAsReadOnlyddeexec opic] @="system"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrint] @="打印(&P)"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintcommand] @=""C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /e" "command"=hex(7):26,00,69,00,67,00,41,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 5a,00,58,00,66,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,45,00,58,00,43, 00,45,00,4c,00,46,00,69,00,6c,00,65,00,73,00,3e,00,21,00,44,00,65,00,40,00, 5d,00,56,00,7a,00,28,00,72,00,3d,00,66,00,60,00,31,00,6c,00,66,00,71,00,60, 00,3f,00,52,00,26,00,20,00,2f,00,65,00,00,00,00,00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintddeexec] @="[open("%1")][print()][close()]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintddeexecapplication] @="Excel"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintddeexecifexec] @="[open("%1")][print()][quit()]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintddeexec opic] @="system"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrintto]
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrinttocommand] @=""C:\Program Files\Microsoft Office\OFFICE11\EXCEL.EXE" /e" "command"=hex(7):26,00,69,00,67,00,41,00,56,00,6e,00,2d,00,7d,00,66,00,28,00, 5a,00,58,00,66,00,65,00,41,00,52,00,36,00,2e,00,6a,00,69,00,45,00,58,00,43, 00,45,00,4c,00,46,00,69,00,6c,00,65,00,73,00,3e,00,21,00,44,00,65,00,40,00, 5d,00,56,00,7a,00,28,00,72,00,3d,00,66,00,60,00,31,00,6c,00,66,00,71,00,60, 00,3f,00,52,00,26,00,20,00,2f,00,65,00,00,00,00,00
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrinttoddeexec] @="[open("%1")][print(1,,,,,,,,,,,2,"%2")][close()]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrinttoddeexecapplication] @="Excel"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrinttoddeexecifexec] @="[open("%1")][print(1,,,,,,,,,,,2,"%2")][quit()]"
[HKEY_CLASSES_ROOTApplicationsEXCEL.EXEshellPrinttoddeexec opic] @="system"
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