Hello there, Welcome to Windows7forums!
First off we need a little more information then that.. Which version of Windows 7 do you have installed? (Also, which variant; 32-bit or 64-bit?) Was this a clean install or an upgrade install?
What is the model of your Webcam? Where did you obtain drivers for your webcam? Windows Updates or from the manufacturers website?
Is the webcam working at all? Or just freeze up and not do anything? What type of interface does your webcam have? USB? Firewire?
If you could answer these questions then maybe we can help you out!