How to manually uninstall MSSQL2005?

When I install the Microsoft Office Communication Server 2007, I have error in MSSQL2005. So I try to uninstall the MSSQL 2005 and install Microsoft office communication Server 2007 again. I get the same error. So I go to this path and uninstall instance. After that I don’t get any error.

C:\\ Program Files\Microsoft SQL Server\ 90\ Step Bootstrap\ARPWrapper.exe/Remove.