I would look up your laptop online. At least try to figure out what kind of webcam you have, and once you do, search for common errors. Or, alternatively, locate the tech-support forums for your laptop's manufacturer. More likely than not, at least one person might have had similar problems, especially when you consider that they've also got the forums and search functions seperated by series and model.
Also look up your drivers, once you've found out what exactly you have. There will be almost guaranteed to be a site that has the exact drivers for your webcam.
If all else fails, reading the PDF manual that came with your laptop might be the way out, because it will most likely mention these things at least in some detail. Unless, of course, I was the only person that actually reads that shit.
Overall, I would just look your laptop online and get to know what's in your computer, because it would come in handy, especially in this situation. Wouldn't hurt to look at basic overviews of how to fix common problems with each of them. I've noticed that you're like one of the most hopelessly tech-illiterate people out there, so I figured that's a problem that needs fixing in itself, so you don't constantly have to deal with having to wait for days to get an answer from us. This also means you need to use your imagination when searching, and be as specific or as broad as you need to be. There won't be a perfect answer unless your computer has this problem with multiple models.
On another note, are you sure that there's no way to manually start up the webcam, such as launching whatever camera utility that's installed on your computer?