This is a simple one that I told my mother-in-law the other day. It won’t protect you from everything, but it will greatly reduce your exposure.
Don’t comply with any request that you didn’t expect.
Put differently – any time your “computer” is proactive about asking you for personal details, credit card numbers, etc then you should flatly refuse, regardless of the terrible things that “might happen”. The same goes for any emails or social media requests that come in.
Don’t do it.