why can't root use screensaver
coz. of that i am unable to lock my desktop.

it says can't start xscreensaver deamon, btw whats this???

i take it you're using gnome. basically the idea behind this is that you shouldn't be logged in as root user, at least not in a window manager or desktop environment. kde does allow this but its probably a bad idea. if you want to log in as root under your normal user, just do an su - and put in your root password. afterwards type logout to exit

is it just not recommended to use X as root
or one can't do it in anyways???
I guess there must be some way around!

On most distros KDM will not allow root to login from its interface, so its not a KDEs fault but the distro maintainers for changing KDMs default configuration. GDM can be configured in the same way but some distros seem to be a bit slack about this issue.

At last i succeeded in finding the way


After login as root in X Window, open a terminal window and issue the following.

xhost +
su

Substitute with any user account name on your Linux machine. For example,

su luqman

Then issue the following:

xscreensaver &

finally lock your screen

Basiclly, there is no need to run xscreensaver as root, couse obviusly U should not even be logged in X as root, little less leave your station loged as root for time needed for screen saver to start, as it is the large security issue

Why not run X as root?

Well, as you may or my not already know, X is quite a big "application", so what if it had a minor bug that would let's say overwrite some conf or other files? Running as root would enable the application to do such a thing, while running as ordinary user it would not be able to do so.
Or even worst, if it had a security bug that allows remote logins, somebody could take control of root account directly insteda of plain user account ( which is bad enough already )

Don't use the name of ROOT in vain...
( Quote from kernel README )

I am not sure why you need to login to X as root? Anything that you need to do as root can be done from your user account. Logging in as admin is what causes most problems on Windows and by doing the same thing, you are not making use of the Linux/Unix security model and putting yourself at risk from crackers and your own mistakes. Its your machine and you can do what you like, but hopefully it won't be something you will regret.