I have had the same problem as yourself, it is highly annoying.
I also found it does this when opening links from emails in Outlook.
After several months of searching I finally found the option to fix this
In IE. Go to TOOLS / INTERNET OPTIONS
go to the ADVANCED tab. In that list. Look for the one that says
"Reuse Windows for Launching Shortcuts" uncheck it.
Thats all there is to it.
Not sure about the fowarded emails though.
eluSive