multiple iexplore.exe *32 running, missing tabs

Using IE9 on Win7
-Previously when I opened new url I simply got an additonal tab and could tab between sites
-Today when I open a new url, a new instatnce of IE launches, I currently have 4 instances of
iexplore.exe *32 using 48-54% CPU
How can I return toseparate tabs for each session and not open multiple instances of iexplore.exe
Thanks

IE9 will have multiple instances showing in Task Manager.

I don't use IE9 so take this with a grain of salt...

Go to Tools > Internet Options and see if this could be your problem.