.docx, .doc, .pptx, .ppt, .xlsx five operations are similar.
1.docx and .doc
1. Win+R, enter regedit, press Enter;
2. For Word 2007/Word 2010, back up and delete the following three key values: (You can right-click and select "Export" to back up the key values to the desktop. Once a problem occurs, you can use the backup to restore the registry key values)
HKEY_CLASSES_ROOT/.docx
HKEY_CLASSES_ROOT/Word.Document.12
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts/.docx
3. For Word 2003, back up and delete the following three key values:
HKEY_CLASSES_ROOT/.doc
HKEY_CLASSES_ROOT/Word.Document.8
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts/.doc
4. Use the shortcut key Win+R, exhale "Run", enter appwiz.cpl, and press Enter.
5. Right-click Microsoft Office and select "Change".
6. Select "Quick Repair"
Two.pptx
1. Win+R, enter regedit, press Enter;
2. Back up and delete the following three keys:
HKEY_CLASSES_ROOT/.pptx
HKEY_CLASSES_ROOT/PowerPoint.Show.12
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts/.pptx
3. Use the shortcut key Win+R, exhale "Run", enter appwiz.cpl, and press Enter.
4. Right-click Microsoft Office and select "Change".
5. Select "Quick Repair"
Three.ppt
1. Win+R, enter regedit, press Enter;
2. Back up and delete the following three keys:
HKEY_CLASSES_ROOT/.ppt
HKEY_CLASSES_ROOT/PowerPoint.Show.8
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts/.ppt
3. Use the shortcut key Win+R, exhale "Run", enter appwiz.cpl, and press Enter.
4. Right-click Microsoft Office and select "Change".
5. Select "Quick Repair"
Four.xlsx
1. Win+R, enter regedit, press Enter;
2. Back up and delete the following three keys:
HKEY_CLASSES_ROOT/.xlsx
HKEY_CLASSES_ROOT/Excel.Sheet.12
HKEY_CURRENT_USER/Software/Microsoft/Windows/CurrentVersion/Explorer/FileExts/.xlsx
3. Use the shortcut key Win+R, exhale "Run", enter appwiz.cpl, and press Enter.
4. Right-click Microsoft Office and select "Change".
5. Select "Quick Repair"
Five.pdf
1. Win+R, enter regedit, press Enter;
2. Find HKEY_CLASSES_ROOT/.pdf and select it;
3. Double-click on "(default)" on the right, and a dialog box will pop up. Enter "AcroExch.Document" in "Value Data (V)" and click OK.
PDF：http://www.scicat.cn/jingyan/20210824/5810984.html
word：https://www.yantu360.net/articles/5/1626528451327840.html