iMac camera not connected?? What gives?

My Dad has a 2006 17" iMac that is fully updated and it does have a camera built in as it should. My Dad also has a cannon all in one printer scanner copy machine hooked up to the computer. As of this moment, when I hit an application like Photo Booth or something else that uses the camera, the program says that no camera is connected.

I did a little detective work and found where someone hooked up an all in one HP device and the scanner took over the "port" that the iSight camera was supposed to be on. I don't know if this is the problem or not but it was all I could come up with. I am pretty Novice when it comes to computers and don't know how to tell what is on any port or how many ports their even are for that matter.

I really want to fix this problem but I don't know how. Does anyone have any ideas??

What happens if you pull the Canon's USB plug out, or if you switch the Canon off?

System Profiler will tell you what/where/how peripheral devices are connected to your Mac.

We actually just tried that and the camera is still not working.... We tried starting up Photo Booth and although the program starts, it says that no camera is hooked up...

I get that too when I connect my PS3 controller to charge it through USB. Usually disconnecting the controller, or in this case your all-in-one, quitting all the apps that use either the all-in-one or the iSight and starting them back up fixes it. If that doesn't work, a reboot has worked for me in the past too. Of course this is only a temporary fix until someone at Apple patches it or the drivers are updated.