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never it will fry. you need good priced gpus with good modded bios with a special mining software unreleased and only available for giant gpu farms located near below 1cent electricity cost. good luck :).

Depending upon Graphics Card you have but Yes it's worth mining on Laptop... i already gave it a try on my machine...

Depends on what currency you want to mine and on the setup of your laptop, mining BTC won't have any effect and will probably ruin your laptop, I mined some electroneum the first week on my laptop which was working fine