1) Issue a Stop A or halt the system.
2) Insert Solaris 10 DVD. At the OK prompt enter:
ok# boot -s
3) Determine the boot disk partition and mount it.
> mount /dev/dsk/c0t3d0s0 /a (or whatever your mount point is)
> cd /a/etc
> TERM=vt100
> export TERM
> vi /etc/shadow and remove root’s encrypted password string so its colon to colon (::)
> cd /
> umount /a
> init s
4) Login as root with no password and set the new password.
> passwd root