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Hi katelynrose,
I recommend taking it back to the retailer and demand a new unit, this should not be happening to new laptop.

Acer Aspire A715-79G has a white backlit keyboard only and does not support RGB or multi-color functionality. You cannot change the keyboard's color. However, you can turn the backlight on or off and adjust its brightness using your keyboard's function keys and system settings in Linux.

Adjusting brightness with function keys
The most straightforward method is to use the keyboard shortcuts built into your laptop's firmware. This often works on Linux distributions without any extra configuration.
Locate the function keys: Look for keys on the top row of your keyboard with symbols resembling light bulbs or the sun. On some Acer models, the keys are F8 and F9 or F9 and F10.
Toggle/adjust the backlight:
Increase brightness: Press the Fn key and the brightness-up key (e.g., Fn + F10).
Decrease brightness: Press the Fn key and the brightness-down key (e.g., Fn + F9).
Turn off: Continue pressing the brightness-down key until the light turns off completely.
Controlling the backlight via the terminal
If your function keys do not work, you can manage the keyboard backlight using terminal commands.
Option 1: Adjust the brightness directly
This method directly changes the brightness level through the system's /sys filesystem.
Identify the backlight device: Open a terminal and run brightnessctl --list to find the device name for your keyboard backlight. It may be something like platform::kbd_backlight or intel::kbd_backlight.
View current and max brightness:
sh
brightnessctl --device='your_kbd_backlight_device' info
Set a new brightness level: Use the set command to change the brightness. Replace X with a number between 0 and your maximum brightness.
sh
sudo brightnessctl --device='your_kbd_backlight_device' set X

Option 2: Write to the /sys file
You can also manually write a brightness value to the file system.
Find the backlight file:
sh
ls /sys/class/leds/
Look for a directory that ends with kbd_backlight.
Turn off the backlight:
sh
sudo sh -c "echo 0 > /sys/class/leds/your::kbd_backlight/brightness"
Turn on the backlight:
sh
sudo sh -c "echo 1 > /sys/class/leds/your::kbd_backlight/brightness"
Note: The your::kbd_backlight part of the command must be replaced with the exact name found in step 1.
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With a computer that old your best bet is ,likely one of the third party sites that have archives drivers for the model. The BIOS is very unlikely to be the problem though. You say ti won't power off or restart. Those are separate actions, so may not be related. As assume by 'won't power off' you mean that in Windows you ask for a shutdown and something hangs?