IE Tabs unresponsive

[canasta]

Why does internet explorer become 'unresponsive' when a second tab attempts to open? This didn't used to happen. It's most annoying and I've had a look around my settings etc and can't see any boxes checked or unchecked to cause this. I think I have IE7. Can anyone help please?? My windows updates are all up to date and I have security in place. After looking at previous postings Ilooked at Firefox but it doesn't have the useful bar I have with the icons for 'print',page and tools with drop down menus giving me useful options. Can this be added to the FF toolbar?