Second Monitor Problem connected with laptop

amy

Hello everyone,   I recently installed ubuntu on my acer aspire 3000 laptop and my lcd is gone and so i attached an external monitor bpl to my laptop.

So the problem here is when i connect the external bpl monitor to my laptop the splash screen come and it freezes in the login screen and i cant do anything after that.

Another time when i boot without the external monitor it goes good. Another time i booted with recovery mode  and from the console i started the xserver and it started well and worked with the presence of the external monitor.

Can anyone pleasehlep me on it ....

THnaks in advance for the people who are going to help me out