My car is making a hideous loud noise

You may find this hard to believe, but I can't hear the noise, and with no other details or observations to go on, the best I can do is offer a few suggestions. If the right wheel doesn't turn left or right when you turn the steering wheel, a worn tie rod end was ignored too long and is broken. The tire will flop around and rub on the inner fender. If the wheel wont rotate when you try to drive forward or backward, typically worn and grinding brakes were ignored until the brake rotor ground down to the cooling fins, then a brake pad or the caliper's piston got wedged in them. If the clicking and crunching of a worn cv joint was ignored long enough it could have broken. You'll typically hear a lot of banging noises when you try to make the car move, but it won't go in either direction. You WILL be able to push the car by hand, even when it's in park. If a noisy wheel bearing was ignored long enough, it can come apart and allow the tire to rub on the strut. The car may still move but not easily. You'll also see the wheel tipped in a lot on top. If a coil spring broke, it can catch on the sidewall of the tire. If you force the car to move, the sharp end will tear the tire and destroy it.

Any chance you can post a photo, but I think you found the cause of the problem. Brake pads never wear down exactly evenly so a grinding noise will always start on just one side. Once the metal-on-metal grinding starts, it will tear up the brake rotor very quickly. Most of the time all you'll need is a new rotor, which is pretty inexpensive, and a new set of brake pads.