Hey there!

It sounds like you’re on the right track! The black screen with a dash usually means the bootloader (GRUB in this case) might need some love. So, you’ll likely need to reinstall GRUB on your old Acer.

Here's a simple way to do it from your Fedora Live USB:

1. Open a terminal (if it’s not already).
2. Run lsblk to confirm that your old Acer’s drive is /dev/sda.
3. Mount the Fedora partition with something like:

   sudo mount /dev/sda1 /mnt
   

   (Make sure /dev/sda1 is the correct partition; adjust if needed).
4. Install GRUB by running:

   sudo grub2-install --boot-directory=/mnt/boot /dev/sda
   

5. Then create a new GRUB config with:

   sudo grub2-mkconfig -o /mnt/boot/grub2/grub.cfg
   

6. Reboot and fingers crossed, it should work!

It sounds a bit like magic (or some weird old ritual), but it should help your Acer find its way. Give it a shot! If it doesn’t work, let us know exactly what you see. We’ve got your back!