HP Paviilion ZD7000 display problems

[robrpb]

My cousin has an HP Pavilion ZD7000 (zd7020us) laptop. I replaced the dc power jack on it. I powered it up without the battery and windows XP Home loaded with no apparent problems. I then shut down the computer, removed the power cord from the dc power jack and inserted the battery. Then I plugged in the power cord and when I started it up the display was not working. The background would brighten a little, but no images or text. I could hear Windows music as it started okay.

I then connected an external monitor. When I started the computer the Windows logo appeared on the external monitor. In the boot up sequence for the next screen after the Windows logo the external monitor went blank, though the computer seemed to complete the process okay because I could hear the windows music as if everything was normal. Your help is greatly appreciated. Thanks.

[glc]

What happens if you remove the battery again?

[robrpb]

glc, I forgot to mention that I tried that and it did not fix the problem. I just tried removing the battery again and there is no display. It brightens a little as it boots up, windows music plays that it is booted up.

I guess I should have left the battery out and the power cord in the dc jack. I have also tried removing and reistalling the the power cord in the dc power jack.