There are webcam programs online, some free, some paid, some free to try, then pay if it works.
Do a Google search on your brand of webcam, you'll come up with leads. Try the free ones first, you never know, you may find a good one. If that doesn't work, check out the free to try ones.
Usually, there's a free option for webcams, but it may take some searching, and lots of trying out different ones to get the right one. Prior to doing anything, you should backup your computer & create a restore point.
Then when you download each app to try, make sure that you manually scan each one with your AV, prior to installing it. While there are many useful apps for free on the net, some can have viruses, spyware or malware within the download. The app may install perfectly fine, but other things may too, things that you don't want.
And as TrainableMan has stated, you'll need to make do with Vista drivers. That's what came with my laptop computer, and although Win 7 Ultimate x64 runs fine, most of my drivers are Vista ones.