When migrating from McAfee to another antivirus, you need to uninstall McAfee Enterprise. When you have not installed it using GPO, it may become quite the task if you have a lot of clients to uninstall the product from. If you have a Windows Domain (optionally using GPO), you can do the uninstall via a logon script.
The installation can be performed by manually uninstalling the product using msiexec. This initiates a proper uninstallation procedure, and will result in a silent uninstall of McAfee Enterprise. Depending on the version you're using, adjust the GUID you see here: