I changed my computers settings

[yuuummm]

i changed my computers administrator setting to something lower in authority which isn't letting me download anything or change any other settings. how do i change it back to the administrator?

 

[nhasian]

Here are detailed step by step instructions with pictures:

How Do I Use the Windows System Restore Utility?
How Do I Perform a Startup Repair or Repair Installation of Windows?
How Do I Perform a Clean Installation of Windows?