You wouldn't get your brain hacked, that's silly. It would just be a better version of the currently existing human interface (keyboard input, VGA output).
If your desktop gets hacked, you don't worry about someone hacking your fingers or eyeballs, do you? Well with this brain interface if your computer gets hacked, the worst thing would happen is that the hacker would beam annoying images directly to your brain (instead of displaying it on your VGA monitor) and maybe fuck around with your keyboard mappings so your brainwave commands to the computer don't work properly.
Solution to a hacked PC would be to disconnect it from your brain electrode and de-hack your PC manually, or get another PC.
Hopefully the connection from PC to your brain would be wireless, so a hacker can't actually zap your brain with electrical voltage. But even if it's wired, you could put a good mechanical fuse or circuit breaker in between the PC and your brain so only tolerable voltages are ever transmitted.