Follow these steps:
1. Open command prompt (Start->Run->cmd),
2. Enter the following command, then press ENTER
3. Enter the followin command, then press ENTER:
This should open the computer management console.
4. Go to local users & groups->users. Right click on any user and select “set password”.
If you get a “access denied” do the following:
then use following commands
1) net user test /add (this command will make test named user)
2) net localgroup administrators test /add (this command will make test user as administrators rights)
and use net user command to reset your admin. password