Maybe try removing it with Revo Uninstaller and then trying again. Or give Malwarebytes free a run to see if it finds any problems. Switch your Firewall of temporarily just to see if it is that which is stopping it.
Hi I have just found out how to remove WOT for Vista go to Tools Add-Ons, Extension, and remove it there. I must have some thing stopping the warnings coming up. Revo won’t remove it nor will add remove. Says it has and the Icon goes away.