“Internet Explorer has encountered a problem and must shut down”

In our office we have 3 computers, not networked, but sharing a wireless cable network. This message, “Internet Explorer has encountered a problem and must shut down,” started appearing last Friday on all three computers. Two of them use IE7 and 1 uses IE6.

We use Windows Defender, Spybot, Spyware Blaster, and AVG8 to protect the PCs.

Does anyone have an idea what’s up?

Many thanks,
Hellgate