MySQL installation failed with error 1045.

Lately I had some problem of MySQL installation when developing MySQL related applications.

I can't get into MySQL Administrator to configure MySQL system because I installed MySQL several months ago and I forgot the password of root.

Error no. 1045 occurred when I uninstalled my old MySQL system and re-install a new version.

Here is my way to resolve 1045 error to share with all MySQL Developer.  

OS Version: WinXP, Win7

MySQL Version: 5.5.10

My ways to resolve 1045:

1. Manually clear leftover. 

2. Use Revo Uninstaller.

1. Manually clear leftover.
   • First, uninstall MySQL from control panel and reboot.
   • Open command window in Program list, or input "cmd" in Run from Start on left-bottom corner.
   • Type sc delete mysql to remove leftover MySQL Service. (If your service is different, please right click on My Computer, select Manage -> Service to look up your service name.)
     
     
   • Go to this path: C:\Documents and Settings\All Users\Application Data\MySQL\MySQL Server 5.5 to delete MySQL Server 5.5 folder
     
     
   • Open registry editor (Run -> type "regedit"), and delete the following 2 keys.
     HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\Folders\C:\Program Files\MySQL\MySQL Server 5.5\
     
     HKEY_CURRENT_USER\Software\Microsoft\Windows\ShellNoRoam\MUICache\C:\Program Files\MySQL\MySQL Server 5.5\bin\MySQLInstanceConfig.exe
     
     
   • Then MySQL can be installed to windows system successfully.
     
     
     
2. Use Revo Uninstaller:
   Use Revo Uninstaller to uninstall MySQL and remove related registry and files.
   You can download Revo Uninstaller here.
   http://www.revouninstaller.com/revo_uninstaller_free_download.html
   • Install Revo Uninstaller, and then launch it.
     Click on MySQL Server 5.5 to run uninstall.
     
     
   • Click Next to launch MySQL Uninstaller after safety check.
     
     
     Click Next
     
     
   • MySQL Uninstallation finished.
     
     
   • Run step.4, click Next to analyze system by Revo Uninstaller.
     
     
   • Click Select All -> Delete to remove leftover keys in registry.
     
     
   • Click Select All -> Delete to remove leftover files.
     
     
   • Reboot system is required to clean leftover files according to Revo Uninstaller's instruction. Before rebooting, we have to remove the service first.
     
     
   • Open command window in Program list, or input "cmd" in Run from Start on left-bottom corner.
     
   • Type sc delete mysql to remove leftover MySQL Service, then Reboot. (If your service is different, please right click on My Computer, select Manage -> Service to look up your service name.)
     
     
   • MySQL can be installed successfully after rebooting.