Click Cancel to dismiss the Font dialog box.
Click Close to dismiss the Customize Keyboard dialog box.The shortcut key is now assigned to apply strikethrough formatting. (A good combination to consider is Alt+Shift+S or Ctrl+Alt+S, neither of which are used in a default installation of Word.) If the combination is already taken, that information shows just below the Customize Keyboard dialog box, and you can then change to a different shortcut key. Just hold down whatever combination of the Alt, Ctrl, and Shift keys you want, and then press the desired key to go with that combination. Type whatever shortcut key you want to use for the strikethrough format.(As you move the mouse pointer to get ready to click, the mouse pointer may change back to an arrow instead of a clover this is OK.) When you click, Word displays the Customize Keyboard dialog box with the insertion point blinking in the Press New Shortcut Key box. Click on the Strikethrough check box in the Font dialog box.The mouse pointer turns into a clover symbol.