Using simple command line tools on a machine running Windows XP we will obtain system level privileges, and run the entire explorer process (Desktop), and all processes that run from it have system privileges. The system run level is higher than administrator, and has full control of the operating system and it’s kernel. On many machines this can be exploited even with the guest account.

Follow these steps:
1. open command prompt (Start->Run->cmd),
2. enter the following command, then press ENTER]:
at 15:25 /interactive “cmd.exe”
Lets break down the preceding code. The “at” told the machine to run the at command, everything after that are the operators for the command, the important thing here, is to change the time (24 hour format) to one minute after the time currently set on your computers clock, for example: If your computer’s clock says it’s 4:30pm, convert this to 24 hour format (16:30) then use 16:31 as the time in the command.
When the system clock reaches the time you set, then a new command prompt will magically run. You’ll notice that the title bar has changed from cmd.exe to svchost.exe (which is short for Service Host). Now that we have our system command prompt, you may close the old one. The difference is that this one is running with system privileges (because it was started by the task scheduler service, which runs under the Local System account).
3. enter the following command, then press ENTER]:
compmgmt.msc
this will open the computer management console
4. Go to local users and groups->users.
Right click on any user and select "set password".
its done now...

if it says access denied do this


start>run>cmd

net use \\(your ip add)\IPS$ /u:Administrator

or

start>run>cmd
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