Dell inspiron 3520 web camera driver download

Have you tried dell.com ?

yes i tried it. i tried that for home user section but there was no driver for web cam.

Dell > Support > Drivers & Downloads
Enter you service tag number and/or "analyze system for updates". A manual search turns up "DellCam" drives, but it requires the OS version.

Unfortunately there is not webcam drivers available, it is a known Dell fault, for the best results you would have to read long post for a different model, but those methods may be applicable to you as well http://en.community.dell.com/support-forums/laptop/f/35...

You may also, try this guide http://www.gurudrivers.com/repair/scan-and-fix-for-hard...

Please report back so we know which way helped you.

I have found the Dell Support site for you:
http://www.dell.com/support/drivers/us/en/04/Product/in...

This would be so easy. Check your link and see - there is no webcam drivers there, LOL.
It is known problem - finding Dell laptop webcam drivers.