Aspine 3000 laptop needs help

Hi, I have recently starded piddling around with laptops,computors in general, so please be gentle,lol. I found my sons ols aspine 3000 laptop out in the garage the other day and its still in decent shape,by looking at it,but I plugged it in and the power comes on but nothing on the screen,so I changed the hard drive which I have done on 3 other laptops and it still won't do anything,the power light comes on,I can hear it runnig.What would be my next step