My bike :(

I have a $300 bike. It's a Schwinn Hybrid, meaning it's built for on and off road. Lately, my chain has been making a funny noise, and I can't go down into 1st gear [it's a 24 speed, so it'd be 1 high and 1 low] without it rattling- and my front brake pad rubs against my tire, causing it to squeak. Now, mind you, neither of my parents put together this bike. It was the last bike they had, so it was the store model. I had to unhook my front tire brake [makes it impossible to text/talk while riding..Kidding, guys. Sorta.], which makes me extremely nervous because I nearly ran into Catherine once, and I had to use both of my brakes. Now, with that unhooked, I have to drag my foot, which is really bad for my shoes, which are my favorite walking/riding/everyday shoes, being they're so comfortable. Dad said it's something wrong with my derailer. This is easy to fix, I could do it, but I'm afraid of messing my bike up beyond repair, being it's my only mode of transportation out and around my neighborhood unless I get this Cavalier from my grandmother [don't ask...I might not even get it. It's got a lot of things wrong...needs a new A/C compresser, etc] and nearly 150,000 miles on it, even though it's a 1998... It's well loved. xD] And, being it rattles when I'm shifting gears, and I cross a 4 lane busy road on it and I go to my 24th speed because it takes me across it faster, and it jerks like a manual car, that increases my chances of getting hit.<br><br>Anyhow. I don't know what's wrong with my bike. I love my bike, even though it has a hard seat, and I don't want it to die. I've only had it for 2 years xD It shouldn't have this many things wrong with it.<br><br><br>This is my bike: <a href="http://i53.tinypic.com/20tmrt5.jpg"; target="_blank" class="bb-url">http://i53.tinypic.com/20tmrt5.jpg</a>.