You need to make sure IIS is installed because if you are not getting reporting services in 2005 it is related to IIS because it is IIS dependent.

Microsoft have covered how to manually remove SQL Server 2005 in the link below use it to clean up your uninstall. Then you need to download all the files to your c drive which will take at a few minutes, then run setup from your C drive.

http://support.microsoft.com/kb/909967