A week ago, my webcam (Quickcam Pro 4000) was just fine, very smooth.

But then suddenly about 5 days or so ago, it became really slow, like one frame every 5 or 10 seconds instead of more like every second a frame. Very choppy. It used to connect straight away but now it takes a little bit longer to connect. The other person has tried showing the webcam to others and its very smooth. The problem is my MSN or webcam, not theirs.
I did not change a thing in the settings, not that I can think of, really strange.
I have MSN 6.1.0207 and running it on Windows XP.
I have Norton Antivirus and Norton Internet Security.
I have tried to disable the internet security, the same again.
I then read that something about the RTCDLL.DLL file on these forums. So I searched my PC for it. It found 4 different files. in C:\I386, C:\Windows\system32, C:\Windows\lastgood\system32 and c:\windows\winSxS. I dont know if that helps! The webcam works fine on my sisters computer. Her version is different to mine. Mine is 5.1.2600.1106 and my sisters is 5.1.2600.0.
I thought that must be the problem, but I found out that the other person who has a camera has the same version as me, but anyhow I tried replacing the file with my sisters version but there was no difference. Sorry if that is confusing.
now should I uninstall MSN messenger or what?
thank you for any feedback.
dave

EDIT: oh yea, and I have updated my video and sound card to latest driver just yesterday, no help there.