Error on UN-installation of SQL Server 2008 R2 on Windows 64 bit System

I want to un-install completely SQL Server 2008 R2 from my 64bit system. When I tried to install, I experienced a common problem about "INSTALLSHAREDWOWDIR" but I managed to install anyway. Now, I can't un-install.

I even tried cmd but when action is uninstall, it doesn't accept INSTALLSHAREDWOVDIR command.

Here is the error I got;

The INSTALLSHAREDWOWDIR command line value is not valid. Please ensure the specifie开发者_StackOverflowd path is valid and different than the INSTALLSHAREDDIR path.

Note that, this error is NOT for installation, it's for removal of SQL. Regards