How to make yourself admin:
First you can try to give yourself adminstrator rights.
Start > Run > Type in: Control userpasswords2
Then select your user > properties > Group membership > Others > Administrators
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If that didn't work,
Then another option is:
Open CMD and type in: net user YOURUSERNAME *
For example: net user Administrator *
*Don't forget to type in the star*
After that, you should be able to change the administrators pass, if you're allowed to do this, idk your situation.
You can then ofcourse simply use the Administrator account, or use it to give your other account Administrator rights.
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If that didn't work,
Next option:
http://ophcrack.sourceforge.net/download.php?type=livecd
Download this and burn the iso on a USB stick.
Do not just put the .ISO file on the disc, properly burn it with like Nero or Roxio or whatever.
Make sure you have USB device in bios to start up before your HDD.
It will then start up in linux and bruteforce the passwords. You should be able to read out the password when it's done (only takes like 10 seconds).
Ofcourse once you have the Administrator accounts password, you can make your other account an admin.
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If that one didn't work, which it always does for me, this is another good one:
http://pogostick.net/~pnh/ntpasswd/
Plenty of options.. good luck lol