No signal on my laptop screen How do I fix that?, both internal and external monitors recieve no signal thinkpad t42

Sir I'm having problem now with my thinkpad t42, it's not the first time I'm replacing a screen actually it's my third time the first two when on succesfully but this one is on thinkpad t42 and I want to believe that the problem here is not the screen the it should be something else, for after changing the sreen, I did not screw the keyboard and just put some few screws to hold the sreen so I can test and at first I saw light on the sreen but the was no image and after I try againg puting it off and on it just when black there is no signal at all now I have remove the screen and I'm using my desktop flat screen but yet there is no signal nothing at all the computer come on nomally the cd drive light come on and u can hear it steeming but no signal I have changed the ram but nothing it's not working. NOTE = all the other two screen I have changed was with the help of youtube video just like this one so I dont know which part is call what so can this problem be? WHAT SHOULD I DO? I'm confuse now please help

Yeah, got it.It might be a problem from the mother board.May be display adapter or graphics card . Check it.

Try this when you boot it up hold down the keys on that to enter the bios config, this will stop the unit from trying to load an OS now when your in the bios config screen if you have no signal to screen or external vga port then it is for sure a hardware problem and if so my advice is to find a better think pad manufacture. On the other hand if you see a picture and can see the config screen when you turn it on then heres what to look for, first see if there is any settings in the bios that may have to do with auto detect a vga and maybe reset the bios to factory default. Hearing the cd and acting like its booting up prob not motherboard or ram issues but more like the OS has somehow lost the driver for the video card but if you see a signal and screen in the config chances are good its a software driver issue however if you still see nothing on booting into bios then chances are good the video card has fryed and thats why it still acts like its booting. The only other choice now is to take it some where like the manufacture where they have the tools to test it. Last resort throw it in the trash and find a better unit as the screen itself should last for years and years. I dont know what OS is on it but if its windows and the CD is set in the bios as a boot device try putting in the setup CD and booting that if you see a picture on screen then use the CD that came with the unit and re install the OS and this would be prob the last thing you could do to try and fix it yourself because if its hardware the video chip is on the mother board can not just replace it if its on the mother board. Good Luck...

I hope you can find a solution.

I had a lot of problems with a R-60 thinkpad.

IBM makes them for Lenovo.

Here is the link to the hardware manual for your thinkpad.

http://support.lenovo.com/en_US/detail.page?LegacyDocID=MIGR-46464

Check you mother body connection or power cable.