I have a laptop that runs Windows Vista and when I turn it on Windows won't boot. Instead, I get this error message.

Windows has encountered a problem communicating with a device connected to your computer.

This error can be caused by unplugging a removable storage device such as an external USB drive while the device is in use, or by faulty hardware such as a hard drive or CD-ROM drive that is failing. Make sure any removable storage is properly connected and then restart your computer. If you continue to receive this error message, contact the hardware manufacturer.

File: \Windows\system32\winload.exe

Status: 0xc00000e9

Info: An unexpected I/O error has occurred.

Is this an error caused by Windows and can it be fixed? Or is this something caused by faulty hardware inside the laptop?

Vista is not the best of ms software , try disconnecting all external devices and reboot.
It is really worth upgrading to win 7 it is much better than vista which was poor or go to win 8