Steps to uninstall Oracle11g in Windows

​Steps:

• START -> RUN -> Services.msc
• Locate all Ora* services & click on STOP
• Start -> RUN -> Regedit
• Locate HKEY_LOCAL_MACHINE folder in the registry
• Open Software folder
• Delete the Oracle folder under Software
• Open System folder in HKEY_LOCAL_MACHINE
• Open CurrentControlSet folder within the System folder
• Open Services
•  Delete all keys related to Oracle. Every key starts with "ORA.."
•  Close the regedit
• Delete ORACLE_HOME folder
• Delete the Oracle folder in Program Files
• Delete the Oracle reference Path variables.
• Reboot​

note:Error in deleting oci.dll
stop microsoft distributed transaction coordinator (msdtc) service and delete oci.dll file manually.
incase file is not deleted,rename the file and delete it.