Your firewall and anti-spy-ware applications are not the issue in regards to your webcam freezing. It would really help if you gave us the make and model of your webcam and what you are doing when it freezes and any error messages you receive, if any. It would also help for us to know what OS version your system is running and how much RAM you have installed along with the amount of free space on your hard disk.
With that said, when applications begin freezing, which is considered a small application crash, with a hard application crash when you receive a message stating that X application has encountered an error and needs to close. If information is lost we are sorry, and you are given the option of reporting the error to Microsoft, if you have Error Reporting turned On, and if you don't, you should.
Microsoft uses the contents of error reports to determine if issues are present which require fixing on the corporate level, and if a Partner corporation needs to be informed and brought into the loop in order to discover any issues which require patching or updated software. This Error Reporting also may have an answer to a specific issue and when you click Report, you may receive a information and resource page to help you either troubleshoot or receive a fix for that particular issue. The Error Reporting service does not send any personally identifiable information, just the contents of the error. Error Reporting is usually turned On by default with a new OS installation, but you may want to check this out if you never see this window asking if you want to report the error to Microsoft.
Now, when an application continually freezes this is an indication the software has become corrupt. The first phase of troubleshooting is to remove and then reinstall the software application and/or the hardware device. I understand this is a pain and usually not a fun task, but it often corrects the issue because doing this replaces the corrupt files with sound files and allows the process to return to proper functionality.
However, because a webcam uses a lot of resources, some of which must be obtained from an outside source, such as the proper codec to run the video, you may want to click on the webcam Help link inside the IM application you have linked the webcam up to, such as Yahoo. Click on Help, then click on Webcam Help, and this opens a browser window where you can receive help specific on use of your webcam with Yahoo.
I use a Logitech webcam and when I first installed it I had to download the proper video codec from Yahoo. I also needed a certain ActiveX component which I obtained via this process and then answered a series of questions at the Yahoo webcam help area.
If you are certain your video camera is not missing critical components as outlined above, in such that you have been able to receive video and audio through the webcam without issue before it began to freeze, then it is time to uninstall the software and reinstall.
In order to do this you will need to remove your camera from the port it is plugged into. During the re installation process you will be instructed when to hook the camera back up to the port. This is very important, as every web camera I am aware of must install the software first, and hook up the camera when prompted. Hooking up the camera prior to loading and installing the software and drivers can have unexpected consequences, including the complete inability of the camera to work properly or at all.
Now, after you unhook your camera, go into either the Windows XP Add/Remove programs, or the Windows Vista Remove a program version of the XP Add/Remove applet.
When inside the window which allows the selection of software programs locate all entries of software related to your webcam model. First remove the webcams Control Center, (as I do not know the make and model of your camera I am unable to tell you under what title the main options window appears. Each camera has its own Home Center, where you set options, make configurations such as video quality, video window size, etc. ) Then, remove the rest of the items one by one and reboot.
This reboot is essential to finish the removal process. Once you reboot, reboot a second time, and then begin the installation process. Slip the Webcams installation CD into your CD/DVD drive, allow it to load, click Install and follow the instructions on your screen. When prompted to plug your camera in, do so, and continue to follow the instructions on your window until you click Finish.
Sometimes hardware devices come with "extra" software on the installation CD. This software may be related to the use of your camera, but you may or may not want to install it. You may not want to install any video editing trial software, or video/photo editing software due to the fact you already have such software applications installed which you use for these types of tasks. You can avoid having unnecessary software installed by clicking on the Custom Installation instead of the Complete, or (Recommended) installation, which installs everything on the CD, without offering you any choice in what is installed.
If you are sure what is needed software and what is an "extra" application and you do not want it, only select the software you know the camera needs.
Avoid installing software simply because it is *available*. Only install software you are sure you will use, otherwise software seldom or never utilized takes of disk space. Additionally, removing software can cause performance and stability issues down the road. I won't get into the *why* of it, it just does.
If you do not have your webcam CD or are unable to locate it, go to the manufacturers website, browse to the Drivers and Downloads area for your model, and download the software installation package. I suggest you download to either your desktop, or a folder you have created for installation package downloads. This creates a smooth installation process and allows for ease of location if the installation is needed in the future.
You can also use other resources at the Support area of the manufacturers website, read FAQs, troubleshoot, and issues others have written in with. Some webcam Support areas also have a User Forum where you can ask questions and receive additional help from users of your particular webcam. Not all manufacturers offer these types of forums but it is worth finding out if yours does. These users are usually well versed in the use and features of your webcam and are a rich resource.
Good luck and much success with your camera, please have a nice day.