My car squeaks in reverse and while driving?

My car squeaks in reverse and while driving?
Added (1). When i'm reversing, my car squeals extremely loudly. It continues when i accelerate, and appears to disappear when i press the brakes. The sound will continue even when the breaks are pressed, or will completely disappear for short amounts of time. I'm wondering if it's the brakes, even though the noise tends to go away once they are pressed?
Added (2). it's a 1999 Honda Accord

Read more: My car squeaks in reverse and while driving?