Hm. The command line (the line at the bottom of the screen) is not something you can usually shut off. Or do you mean the floating prompt attached to the cursor? The latter is controlled through Tools > Options > Display Floating prompt.
If that doesn't help, I'd recommend a repair install.
Yes, this happens to me at random intervals (Running Windows 8.1 and 10). Simply closing the program and starting it back up usually fixes the issue. Very annoying but not entirely broken.
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If that doesn't help, I'd recommend a repair install.