Webcam problems - possibly because of updates

I really wanted to ask for help because I can't seem to find any solutions for this problem.
Background:

OS: Windows 7 Ultimate x64
Board: INTEL DP35DP
Processor: INTEL Core 2 Quad Q6600 2.40Ghz
Memory: 4.00GB
HD: Multiple - 500GB (4 pcs)

OK, as an additional info I'd like to add that I have 2 installations of Windows 7 Ultimate x 64. I used my installer to install to 2 separate partitions. I did this because I wanted to separate my work and gaming systems. The partition I'm having problems with is the gaming, but note that the installation of windows 7 is almost exactly the same between the 2 partitions. The only difference is the size gaming - 70GB, work - 120GB, and applications installed gaming - games, work - office, photoshop, etc. My problem is the webcam I've been using can no longer be used for messaging and by any application. I bought an A4Tech PK 335 webcam:Welcome to www.A4Tech.com::Product. Since I installed it on both Windows 7 installations, the webcam worked fine, It was even in high quality mode during video chats on Yahoo Messenger. Then for some reason, about a month ago, it just stopped working. Yahoo Messenger, Skype, and even other applications could not see the camera. Sometimes the camera would be detected, but no picture, there was just a white box where the images should be. And Yahoo Messenger's webcam function says that there are no cameras detected. I suspect that it was a Windows 7 update that caused this because during the time I was using my gaming windows 7 a lot and I think it performed an update. When I tried using my work Windows 7 installation, the camera worked fine. Which is why I stopped my Work copy from updating and so far the camera still works on that installation. The Gaming installation works fine on everything else except for the webcam problem. I've tried checking device manager on both installations and they are exactly the same. There is a problem with a PCI and Multimedia device ( I think its my old Pinnacle PCI TV capture card - there are no more drivers for it) on both installations. But apart from this, both installations show the same device manager info.

I really hope someone can help me out. I use my webcam a lot because my wife is in another country and we talk online a lot. Having to reboot and use the work installation is really annoying. In case someone can help me out I'd like to extend my thanks and hope that I can return the favor somehow.

Thanks,

This is strange because I looked at the site of the webcam and it said that it is a driver-free cam. But on the support page there IS a driver for it. So you can try some of the following solutions:

1. You can try to do a system restore to a month ago, when the camera was still working.
2. You can download the latest driver and see if that helps: Welcome to www.A4Tech.com::download driver
3. You can go to Add\Remove programs and choose to see also Windows updates. Sort them by date. Then you can start uninstalling them from a month ago, one by one, each time restarting and trying the cam. I know this might be a little annoying but if it's just one update that is causing the problem, this is way to find it. Then you can hide this update from it ever installing again.