Acer Aspire 7720G dead screen question

FastSnail

Hello everyone,
I hope that you all enjoy the holidays.  I have a Acer Aspire 7720G - dual core T5450 - Windows Vista. 2 days ago, for no apparent reason, it refused to boot.  It only boots in safe mode, and then I got a 'dead screen' .  The laptop display is pitch black, while an external monitor delivers these 2 pictures  http://http//www.packardclub.fr/temp/HardyJerome1.jpg   .http://http//www.packardclub.fr/temp/HardyJerome2.jpg  . What do you think is broken? Graphic card? Motherboard? Something else?
If you believe it is the graphic card, this Acer is equipped from the factory with https://www.amd.com/en/support/graphics/amd-radeon-hd/ati-mobility-radeon-hd-2000-series/ati-mobility-radeon-hd-2600. I cannot find this card on the market. I could find:  https://www.amd.com/en/support/graphics/amd-radeon-hd/ati-mobility-radeon-hd-3000-series/ati-mobility-radeon-hd-3470
Do you think that I could use this card as a replacement of the HD2600? Will it need a BIOS update? A driver update? Thank you very much in advance for getting back to me.
Happy holidays,
Jerome