I have an old dell vostro 1520 with a nvidia grapics card. I have a windows/ubuntu dual boot.

I recently tried to connect a new lenovo external screen. Upon connection that laptop screen went crazy, so i rebooted the computer.

After that, when i try to boot ubuntu, i'm stuck at the purple screen with the colored stripes, whether i boot with or without the external lenovo screen connected.

I can still boot fine in windows.

I tried holding shift while booting linux, and changing 'quiet splash' to 'no splash', which doesn't change anything. I also tried nomodeset, which leads to the screen being stuck at the purple screen, without the strips.

Interestingly after having a failed boot in ubuntu with the lenovo screen connected, if i boot with windows afterwards, only the external screen is recognized, and is now called 'standard screen for laptop'

Any help or links to help will be greatly appreciated!