Hi there and welcome
you have three options here which I will list out. As this is security, there is no simple solution, but any of these three options will work, it will just depend on how comfortable you feel doing them.
1)Reinstall the computer. This means you reinstall windows but lose all your data on the computer. It is not ideal, but the easiest way to do this. For this option, on the log in screen, hold down the SHIFT button and with it held down, click the power icon and choose restart. Keep SHIFT held until it has restarted into a menu. Choose Troubleshoot, then Reset my PC. This returns the PC to new, so you can set it up again.
2) Take it to a computer store, have them take out the hard drive and copy out your data to another disk. Then the reinstall can be done and you wont lose your data. Programs you have to install again.
3) This is the most complex solution, but it will mean you will not lose your data or programs and can do this yourself
Save this file to your computer
After downloading the ZIP file, locate it and double-click on it. Select "Extract All." Extract the files to the same folder the ZIP file is in.
The .ISO file is a CD image file used to create a bootable CD. The file must be burned as a bootable CD - not as a data file - to a CD. If you don't know how to do this, the simplest method is to download the freeware ISO burner at the link below:
Choose the appropriate version for your system (at present, version 3.1 for Windows Vista and Windows 7.) Download the installation file to a convenient folder. After downloading it, right-click on the file and select "Install." Now go back to the .ISO file, right-click on it, and select "Copy image to CD."
After burning the bootable CD, put it in your problem computer and restart the computer. Tap anykey to have the disk load.
Follow the instructions given on the screen to change the password ***** the target account.
This video shows you how to do the instructions I explained
After completing the reset procedure, remove the CD from the drive and restart the system. The password ***** the target account is now set to whatever you chose.
You will have to do one of these three options to get access to the computer again.
If you have problems, or would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service, that would be greatly appreciated.