depends son ur board some boards can't stand i3 or i5 so check the specification of the board first if it's no problem just YouTube it and u will find it easy .
remove the battery and use the charger if it wont open then the charger need replacement. if it worked check the battery maybe corrupted or life time .
first u need to check the connector cable from monitor to the board it's likely the issue here , maybe not connected well from both side u better check or corrupted need a replacement.
u can hear ur fan working if it's not u need to clean it or change it , u need to check ur battery if it's shuting down the battery might be the problem .
i didn't understand the question , if the charger is loose u can open it and change the cable not that hard if the laptop charger slot is loose u need to dissemble the laptop and replace the power slot or hold it with super glue .