The lens does not open. I dropped it and now the lens does not open

Was the unit dropped or were any liquids messed onto the lens assembly previously ?
If dropped (particularly if the lens was open) the lens drive mechanism might well have suffered damage.
If liquids, particularly ones containing sugar, were accidently messed onto the lens assembly, then the sugar becomes sticky as the liquid dries, effectively glueing the mechanism in place.

clicking is done when the lens unit/camera i ok,when the camera dropped lens unit must be damaged,so it should be serviced/replace with a new unit

Bad news - there is no DIY fix for lens damage. The drop likely damaged the lens tube (housing) or jarred the zoom mechanism off of its track. If you attempt to fix it yourself you are likely to worsen the damage, so the camera will need professional repair.

I know this is not the answer you want, but when you dropped the camera you damaged the lens tube (housing) and your camera will require professional repair.

I already tried posting this but I think it falied. Just in case, here it is again!

I just now fixed my own Nikon S220 (very similar to 210) which suffered the same fate as yours. However, I laid my camera down on a cushioned foot-rest (you could use a couch cushion or pillow on a table) with the lens facing UP, pressed down on both sides of lens front gently yet firmly, and BAM, the lens went back in all the way. I turned the power back on and the camera is good as new (except for the small dent from the fall of course).

I suggest you try this before spending $100 on repairs and/or buying a new camera!

Lens errors are fairly common. Usually it's sand or grit interfering with the lens extension mechanism. Or the camera's been dropped with the lens extended. Or the camera has been powered on, but the lens had been blocked preventing its extension. Or the battery ran down with the lens extended ...

Here's some things that you can do to try to correct it. They only seem to work for less than 50% of the lens errors, but if the camera is out of warranty, they're worth a try:

http://camerarepair.blogspot.com/2007/12/fixing-lens-error-on-digital-camera.html

Try the procedures in this tip.

Lens errors are fairly common. Usually it's sand or grit interfering with the lens extension mechanism. Or the camera's been dropped with the lens extended. Or the camera has been powered on, but the lens had been blocked preventing its extension. Or the battery ran down with the lens extended ...

Here's some things that you can do to try to correct it. They only seem to work for less than 50% of the lens errors, but if the camera is out of warranty, they're worth a try:

http://camerarepair.blogspot.com/2007/12/fixing-lens-error-on-digital-camera.html

This is not a simple fix
Indeed it may not be fixable
With so many new models coming on line all the time parts are usually available
Kodak Support will advise

Motor mechanism is shot Sony customer support for advice My - bet? New Camera And treat this one with some TLC