Navigate to HKEY_CURRENT_USER/Software/Microsoft/Internet Explorer/Main
If there is a value called TabProcGrowth , set this to 0 , if the value does not exist, create it as a REG_DWORD type with a value of 0.
Not sure if this is the problem , TabProcGrowth does not stop multiple tabs opening up in internet explorer , it stops internet explorer creating multiple processes in task manager depending on the number of tabs open in internet explorer.