I installed drivers amd64-microcode and nvidia-340 on my Elementary OS and I restart it. Unfortunately I can't turn on my computer. I was trying in recovery mode, but it doesn't work. My copmuter screen blinks and next I see only black background.
What should I do now? How can I remove this drivers?
I'm so sorry, this kept me up until 3AM a few weeks ago.
It sounds like your situation is slightly different than mine. I could not even get into a grub menu. So, take this with a grain of salt, but maybe it will help someone in the future. Also, if you're still having this issue, you might be able to use the chroot trick.
First you should try the nomodeset fix to see if you can boot and purge the drivers. If you make it past grub and to a black screen, try using ctrl+alt+f1 to get on tty1. If you can get on tty1, purge the drivers.
Next, if you can't make it past grub, and you can't boot into recovery mode, the first thing to do is make a live-usb with your favorite distro. After that, you could try using chroot from a live-usb to purge the drivers
If that doesn't work, try to make a bootable version of boot-repair
As a last resort, use the live-usb to copy all your important files onto an external and then use boot-repair's uninstall OS option to reinstall the operating system a few times. Be ready to rescue your grub
