backlight out on monitor not lcd, inverter or light

Hi there a mate asked me to format his laptop a dell inspiron 6400 and when he gave it to me everything worked fine but when i tried plugging my mouse into a back usb the monitor went dark. Everything else works fine under strong lights i can see everything on the monitor but it is still really dark. I restarted and pressed F8 when starting up to put in safe mode but instead i got a choice to do a diagnostic test so did and on the lcd test the backlight passed and inverter passed but the graphics failed. Although when the graphics failed it said the keyboard took too long to respond so it might have been that i had to press something as i couldn't see properly the screen was full of what looked like should be multicoloured lines and at the bottom had writing in black i couldn't see. Reason i say this is because i did the directx video diag tests when logged on and they all passed so didn't think it could be graphics!

Right i took the keyboard off the laptop and directly behind the usb i tried to plug the mouse into is the connector for connecting the lcd to the rest of the laptop the wide part that slots into the motherboard. There's some tape that loops over the connector as wide as it that sticks to the mb and under this tape in the triangular gap made is a loose piece of metal about half cm wide with 2 holes in it when i try to get it it seems it's stuck to something i can't see so i can't tell how long it is but can't be too long probably an inch. The gap is too small to get really in there and haven't got the right tools to take the lappy apart. I don't know if plugging the mouse in could have broke something but the usb didn't work either.

It has a lot of viruses that's why he wanted it formatting i can't even install anything exe files work though just not for installing and for some reason i can't get into user accounts in control panel!

Sorry to go on thought id explain it the best i could any help would be really appreciated as i'm getting the blame for it even though i only had it for literally 10 minutes!

Cheers

 

What happens on an external display? Does that work? If it does, plug the machine into an external display, format the drive and reinstall Windows, and see what happens. Though it seems to be some sort of hardware problem at the moment, that you mention there's a ton of junkware and such means that there's a lot of software variables to cross out before you can be sure.

 

Thanks for the reply. I used to have a lappy that flickered constantly and the light went on and off all the time i had to bang the corner were screen met keyboard to get it back on it was like that from brand new. After about 6 months it stopped and worked fine without doing anything. I've tried doing the same with this banging it to no avail i feel like banging it off my head. It does work on external forgot to mention that. Is there anyway of formatting the drive without having to use a windows disk coz it's not having it the disk loads up whilst the laptop is logged on but nothing can be installed. I know there's code of a few lines that you put in a bat file and when you open it it wipes your hdd but i don't know if it damages it it is a virus but could be helpful in situations like mine!

 

You have to boot from the Windows CD. Press F12 when the BIOS loads and select the CD/DVD option. That'll get you into the Windows installer and that'll let you wipe the drive and re-install the OS.

Since it works fine on an external display, that probably means you've got a bad backlight or a loose connection. In the advent of a bad backlight, you most probably should replace the screen, unless you're comfortable cracking open an LCD.