sorry,for the late ,(i lost a good friend with covid19)
you asked me about service tag ,it is <Service tag removed>
i found on the internet many motherboards for inspiron 3521,with some different specification
my laptop inspiron 3521 (intel corei3) .but some others are core i5 or i7
so ,do you think i can use one with i5 or i7?
thanks(sorry again,and stay safe)