My LG Stylo 4 no longer gives an option to transfer files and is only able to charge when plugged in to my computer. I've tried a few solutions I've found on Google (USB debugging or changing cable), but nothing has worked.
Either the USB cable is bad (there are 4 wires, 2 for data, 2 for charging - one or both data wires can be damaged, but the phone will still charge), or the USB port in the phone got disconnected and has to be replaced. If you don't have another cable, borrow one from someone and try that first. Replacing the cable is a lot cheaper than replacing the port.
Welcome to Android Central! When you connect via USB and swipe down the notification panel, do you see a USB icon? If so, tap it and make sure MTP is selected.
So just to be clear -- you're saying that it worked on another computer, and you were able to transfer files? If you connect with the original computer, does it still not read? If that's the case, then it's a problem with the computer. Did you already try all of the other USB ports on the computer?
What OS version is the problem computer running?
See what happens if you reinstall the driver: https://www.lg.com/us/support/software-firmware-drivers