Your problem could be any of these things:
Razer Chroma and Overwatch haven’t been friends for a while. Check out the known issue thread, and also this extra info for complete removal of the SDK components.
This is your Realtek Audio driver crashing, which could be restarting in the background causing the issue. More info here: https://www.reddit.com/r/techsupport/comments/3rxyyr/atkex_cmdexe_has_stopped_working/
This might be holding your alt-tab captive, so I’d try without it running.