After I turn the device on, its screen is stuck at "starting..." for a long time. It hasn't change into the regular screen, and the light behind the button was still red (didn't become green). Is there a fix for this?
Try flashing the firmware. To get into firmware update mode, hold down the right button when turning the EV3 on. (You can also reset the EV3 without removing the battery by holding down the back and enter buttons for a few seconds.)
You can find much more detailed information on here.
It sounds like the firmware needs a factory reset. Try this:
- Remove the battery for 10 seconds and then put it back
- Hold the Center and Right buttons until "Updating..." pops up on the display
- Connect the EV3 brick to your PC using USB
- Update the firmware using "Tools" -> "Firmware Update" in the EV3 software
Have you tried another OS like LeJOS that can be installed on an SD card? Insert that into the brick and start the brick up. I don't know if this will work, as I don't have a non-functional brick to try it with.
Have you ever had your brick connected to your computer and communicating properly? Are the comm port drivers loaded for the Lego brick to be able to communicate with your computer?
Do you have a friend with a working brick that can test that you have functioning comm drivers by connecting their functional brick with your computer?
What was the scenario that led your brick to stop working properly?