Windows forum: Get best and 100% working solution: Hack Windows 7 (Become Admin)

Steps:-

Start the pc, tap F8 continuously on the boot screen to get some windows start-up options.
Choose "Start windows normally" option and turn the UPS off immediately.
Then turn on the PC again, let it load.
After that you will be prompted with two options in the boot screen (again), select the first option - "Launch Start-up Repair(recommended)"

After 5 min, It will ask you to "restore defaults", select "Cancel" option and let it continue. Wait for 15 to 20 mins.

After 20 min, an error report screen will pop-up, asking to send information or not.

Ignore it, click on "View Problem Details" arrow, scroll down to the end of the report, then click a link stating X:\windows\ something...something (the link starts with an"X")

Another Window will pop-up, and will look like a notepad (it is a notepad)
Click File on the Menu-Bar, then select Open, and another window will pop-up (that's just too many windows!)
Navigate to C: drive (or whatever drive on which windows is installed), click Windows, then System32, after that click on the arrow beside the "File Type" option and select "all files".
Then search for a file named "sethc"(this is the shortcut to stickey keys), rename it to something else (Eg:abc)
Search for cmd, make its copy and rename the copy as "sethc".
Close everything, restart the PC, go to the log-in screen, press shift 5 times, until a cmd (command prompt) pops-up.

Type in "net user administrator /active:yes", and this will activate the default administrator account of the PC.
Change/delete/manage/reset passwords from there.
Or you can directly change passwords from cmd, type "net user (admin/any admin account's name) and then after a space put an asterix.