I have removed all McAfee applications from the system but McTray.exe still show in the system notification area icons as McAfee status: OK
Did you follow the procedures outlined in this Link?:
Not certain as to why you have chosen to remove your product? Were you having issues, or personal choice?
Irregardless, you need protection especially in these days of computing. Are you saying that after removing (Through your Control Panel, I assume) that you were capable of (Opening) the McAfee UI, and it stated "Your computer is Secure" ?
Could it be that you were removing another Application that is mistaken to be a Security Product called "McAfee Security Scan Plus"?
Which basically has no protection capabilities at all. It is often inadvertently installed, along with other similar programs from other Vendors as a (Optional Offer) during Adobe Flash Player Downloads.