I disconnect my windows 7 computer from the domain and now I all I have is a STANDARD user account(no administrator local account). And I lost all the data of that account. When I tried to access that particular USER folder using this standard account I got a message that I need an "administrator account privilege". How can I have an administrator account so that I can take ownership and access the data I lost when I disconnected to the windows 2008 r2 domain? Thanks
Boot the system into safemode (Hold F8 before the Windows logo appears) and select the Administrator account (I don't think it should have a password). From there, you can flag your other account as an administrator through the control panel.
Enable and/or unlock Administrator account in Windows
If the normal option of booting to safe mode doesn't give you access to the administrator account, or if you don't know the password, then linux is your answer.
The utility you'll be using is chntpw. It's a linux program designed specifically for enabling and unlocking accounts on Windows. It's usage for Ubuntu is detailed here, but it can be installed on other distributions too.
To avoid a long download and complex setup, I recommend the chntpw-specific USB or CD image (~3MB) of the Offline Windows Password & Registry Editor by Petter N. Hagen. The latest release is 05/11/2011, but I can verify it works on current software. I created 2 dummy accounts on Windows Server 2012 (essentially Windows 8, just server-fied), and I was able to successfully blank the passwords on them both as well as enable the one I'd deliberately disabled.
In order to make a USB disk mountable, you'll need Administrator access. So if you don't have access to a friends computer, you're stuck going the live CD route. In addition, many user accounts are blocked from burning CD's by default and either need permissions enabled for it or require a program that was installed prior to losing the Admin account. In short, you might still need a friends computer.
A summary of his USB creation instructions:
A summary of his CD creation instructions
Once you've created the CD or USB disk and have booted from it, you just have to follow the on-screen instructions to get through it. Take your time and read the prompts (there are several), and you'll get your Admin account back.
If you need help with the more specific instructions, feel free to leave a comment and I'll go into more detail.
Link to USB image: http://pogostick.net/~pnh/ntpasswd/usb110511.zip