(Re) boot the system with:
b -fl 0,1 dka0(Replace DKA0 with whatever is appropriate for your installation)
At the SYSBOOT console:
SYSBOOT> SET/STARTUP OPA0:
SYSBOOT> SET WINDOW_SYSTEM 0
SYSBOOT> SET WRITESYSPARAMS 0
SYSBOOT> CONTINUE
$ SPAWN
$ @SYS$SYSTEM:STARTUP
$ SET DEFAULT SYS$SYSTEM:
$ RUN SYS$SYSTEM:AUTHORIZE
UAF> MODIFY SYSTEM /PASSWORD=newpass
UAF> EXIT
$
