Postman not starting.. (Windows 10)

I was using Postman to get oauth2 tokens and it was working fine. When I needed a new token (for a different account), I could not because the browser is cached the old user. So I tried to remove all the cache for the browser in the developer tool. After that my postman has become unstable.

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I tried to reinstall, still the same issue. How can I remove postman completely and then reinstall?

Thanks.
Niranjan