Laptop Freeze when it is charged and used Simultaneously

I have dell inspiron 5110 , the problem is that it freeze when i put it on charging  . I can not used  laptop and charge simultaneously . This issue is resolved when i put windows on my external drive then i can charge and used my laptop simultaneously but not when i tried to run windows on internal drive and charged it at the same time . 
It freeze on Windows 7 as well as 8 [ while reading from internal Drive]