This is specific to an obese individual. For weight loss - is it better to first focus on cardio, and then move on to weights, or is the combination a better approach? And why?
Well, it is difficult to loose weight only with cardio. If you want to get fit and make progress you got to hit the weights and run a lot. And by running I mean sprints because they make your body burn fat and your hearth working. Also, the veloargometer won't do anthing good for you.
Pushing weights makes your body tight. Only cardio will cause you to loose mass but be with very flabby skin and muscles.
First things first: get your diet in order. If you are not eating the right things to help you lose fat (fat, not just weight), no amount of gym work will overcome those calories. Once you get your diet working, then look at what you can do.
Weight lifting is a powerful way to burn a lot of Calories, particularly if you focus on strength. Conditioning is another way to burn Calories. However, I would caution you that as important as exercise is, going with the goal to simply lose weight is going to leave you aimless and cause you to get bored with the regimen.
I recommend you do the following while you are getting your diet in order:
Remember, fat loss is done in the kitchen. Muscle building and conditioning is done in the gym--and it's best done with real and tangible goals in mind. Keep your first goals reasonable. When you hit that goal, increase them a little more. It's that process of beating goals that makes the gym fun. If you go in without any real goals, or goals that are too far in the distance, it demotivates you and you lose interest.