Upgrade from 2008 RTM to 2008 R2 RTM failed due to perf-ReportServer-rsctr.dll is being used by another process

I was upgrading SQL Server 2008 RTM on windows Server 2008 R2 Sp1 to SQL Server 2008 R2 RTM.I got this error " The process cannot access the file 'C:\Windows\SysWOW64\perf-ReportServer-rsctr.dll' because it is being used by another process." " Service 'MSSQLServer' Stop request timed out and this occurred during 'sqlEngineConfigAction_upgrade_shutdowninstance_cpu64 ' phase and I stopped & disabled WMI even though it was not running and did not install process monitor to see who locked this dll. I also shutdown application servers before starting the upgrade to avoid them to attempt to connect to SQL Server. After the failed upgrade full-text search ,SQL Server Replication, Database Engine Services, Analysis Services and Reporting Services status were Failed but others succeeded such as management studio &integration Services etc and then I restarted the server as it was required but as expected after reboot server was still in 2008 RTM and when I queried select @@version.

Do you think I should upgrade SQL 2008 to latest service pack SP4 and upgrade as this bug may have been fixed on latest service packs and then upgrade to SQL Server 2008 R2 or just figure out which process or application that may be using this dll?