need to reinstall mac os x but the command key is broken I have a macbook, after an accident I had, my keyboard doesn't work properly (some keys are not working at all including the command key) recently I m facing some problems like, no sound and no camera working, have found out that reinstalling the mac os x might solve these, any idea how could I work this out? I mean without the restart/command + R method
You can force restart by holding the power button for a few seconds.

If the Option key works, hold that during restart. This will present you with a list of all valid bootable partitions.

If that doesn't work try plugging in an external keyboard.