black square box around desktop items, apllications??

Can someone help me please, when i start my mac up, there is a black box alway outlining a item on the desktop, or for instance when i open firefox, the cancel X in top corner is highlighted?? i have also noticed that in the mac symbol menu there is double of shut down , log off, and others.. can someone help put this straight as it is really frustrating me.. thanks..

maybe ita virus but i thought macs didn't get them..

Thanks

Dan

System Preferences > Universal Access > VoiceOver > Off.

For more info do a search for the other posts that have covered this in the past.