In addition to what Derek suggested, try this: Quit out of InDesign and reboot your computer. If possible, hold down the Shift key when rebooting to turn off autoloaded applications. OPEN INDESIGN FIRST. See if you still have the same problem. If you still do, try Derek's method. If your shortcuts now work, there is probably an application or a browser extension which is stealing your modifier keys. Common example would be an anti-virus application set to do so. Watch carefully as you load programs to see what might be interfering.