When i try to use my webcam on skype, it comes up being used on another application, the cam is built in to my hp pavillion dv9000, how do you get it off and on to skype?

1st You download Webcam Driver.
my webcam install After this install the Webcam driver in the system.
Installation of Webcam Driver
Go to the control panel
Click on the System Icon
Click on the Hardware Tab
Click on the Device Manager s
Select the Unknown Device or printer device where yellow Question Marks sign on it.
Right click on it and uninstall it.
After this go to the top of the device manager and click on scan for hardware changes.
Driver installation Wizard start.
Brows Your Driver from the Hard Disk and click on next.
Driver will be install.

Sometimes the webcam software can 'hang on' to another program if you have been using it elsewhere. Even if you you have exited that program correctly it can still happen.
With my webcam I can reboot it by unplugging it from the USB and plugging it back in after a few seconds.
As yours is built-in you will have to reboot the whole computer, use a keyboard shortcut, (if the machine has one) or 'disable' and then 'enable' the webcam from the Device Manager.