Heh, we have quite the opposite goals. Anyway, the biggest problem is HABIT. Right now you are over weight because of your habits. The hardest part is to change your habits. I need to gain weight, and look at me, I'm still a skiny-ass 145lbs.. Although it's not *that* bad cause I've been going to the gym over the summer. I could still use 20-65lbs and not be fat at all, though.
Anyway.... it's the same no matter what your goal is. Routine and habit. Make yourself a schedule. Stick to it. If you just do stuff randomly, you may be able to lose some weight just cause you happened to do it often enough, but you won't see awesome results unless you are actually very determined. Losing weight is usually a very hard thing to accomplish. But you'll be happy and have no regrets once you accomplish it, if you do so properly.
Don't only do one type of exercise, or you'll be lacking in other ways. Do cardio every day, or 5 times a week. So, let's say you can only run for 1 or 2 minutes. Run for 1-2 minutes three or four times a day. Before/after meals (not RIGHT after, duh), to make it easy as a habit. Once you do that for a week, maybe two, you'll be able to increase the time you can run at once. So you'll be running 5, 10, 15, 20 mins .. Before you know it, you'll be running for hours and not breaking a sweat. I'd say after a good few weeks of solid running, you'll be on your way to being in very decent cardio-vascular shape.
You should start off with just running at first. Once you've done that a bit, hit the gym (but don't stop the running). Start off easy, and always remember to stretch before and after your workouts. Workout a variety of muscles, and don't work out the same ones every day. For example, do upper-body for one or two days in a row, then work out the abdominal area as well as the legs (although running will whip your legs into shape as well). I don't think i need to go into detail regarding specific muscle groups and which ones to workout how much, etc - just go to your gym, and go around each machine, try everything out. The ones you find hardest to do, are most likely to be the ones you should do the most, until they aren't so difficult anymore.
I can't stress enough the importance of your diet when trying to lose weight. Do not stop eating! You want to lose weight, but your health is just as important. If you don't already know very well how to eat healthy, consult your doctor. Cause if you aren't getting everything you need, you won't grow/adapt the way you should and you'll start to have problems. It'll be easiest to reach your goal if you follow a strict and healthy diet, along with your workout schedule. I would go into specific meal details, but I won't, because I'm not specialist/expert. So like I said visit your doctor/nutritionist and figure out what you gotta do.
Good luck, fatass! 😛 😉 😀
-RSI