heyy
i forgot my root passwd but i cant reinstall due to some reason can anyone tell me hw to reterive root passwd

Not knowing what system you have means we can only give general advice.

I suggest you post operating system version, hardware etc.

The general solution is to boot in single user mode using a CD-ROM, then mount the root partition which typically has the /etc directory on it, and manually edit the "passwd" file to remove the password for root.

Altenatively use "chroot" to set the volume as your root and run the passwd command directly.

ya ...im using fedora-7 and i had set the grub loading password ....do i have any way to change or retreive my root passwd......actually i have some important data that i dont want to loose.....

You may be able to boot into maintenance mode (or something similar), but that may ask for the root passwd anyway!
Otherwise, you could boot from a "live" CD and then mount your hard disk to be able to get at the file as described in the first response (note that you delete the password field with the editor, not the whole line).
Once that's done, you can then reboot from your hard disk and login with no password.
Make a copy of that passwd file before you edit it, or you could get in a right pickle if you make a mistake.

hiiiiii.....
thanks i tried the chroot command and i m able to change my root passwd.....but as a security reason....can u telll me hw to restrict it ...i mean i had entered as a user and by using this command i m able to view my root directory .....at this instant its ok for me ...but hw to restrict this....or any user can have access to this............

You have to

(a) restrict the BIOS options for what the machine can boot from, eg only from first harddisk and password protect the BIOS

(b) put the machine in a locked room or cupboard

unless you encrypt the drive you can always remove the drive from that machine and put it in another machine to do the same thing.

Of course once you do that you will be posting a message saying how do you reset the BIOS password or asking where you put the key for your cupboard.