buyer read : 
dell inspiron 3521 motherboard CN-0671DP LA-9104P SR0VQ pentium Cpu onboard

(1) fully tested well and working 100% .
(2) 60 days warranty 
(3) our working time is 9:00 am to 6:00 pm from monday to saturday .
(4) when you place the order , please check if your motherboard is same to our picture and please check if yours motherboard part number is CN-0671DP too .if same , you can place the order .  if your motherboard is no same . please feel free to contact me . 
(5) we will take out the cmos battery before shipment . when you receive the motherboard , you can take the cmos battery from your old motherboard and install on our board .