I am from Dell Social Media and Community. I will be glad to help you to get the drivers.
If you have the Dell Webcam disk which was shipped with the system, then try installing the drivers and software form it first. If you do not have the disk, then click below link and request a backup set of disks.http://support.dell.com/support/topics/global.aspx/support/kcs/document?c=us&cs=19&docid=52002&doclang=en&l=en&s=dhs
You can also go to Drivers & Downloads, enter your service tag number. Under input devices, You'll see Webcam drivers. If they're not there, then try the vista drivers. Try installing the drivers in the compatibility mode.
"Right click on the drivers file, left click properties, left click compatibility. Change the compatibility to Vista. Then right click on the drivers, left click run as administrator."
Let me know if this was helpful or if you need any further help.