Mike,
Thanks for your great suggestion. With the help of NT Offline Password Disk, I was able to enable administrator account and for test purpose I promote user to administrators group.
I was not able to enable administrator account with Startup Repair Disc, when I give the command net user administrator :active/yes I was getting successfully completed message but it was not enabling administrator account. May be I was doing something wrong.
Thanks again guys for your prompt and good advance.
Regards,
Magicguy.