Sounds like your PCs been riddled by one of those so called browser hijack schemes that nasty people out there are sending out.
Makers of various antispyware tools try to keep track but some fall through the cracks, the problem is that this trojan horse software scatters many different bombs across ones hard drive. These bombs get triggered by changes the hacker makes to the system registry and other core files. These multiple bugs on your computer create those multiple instances of the windows internet explorer software problems. Perhaps the ultimate tool to attack these bombs is Hijackthis, a system that requires serious study but that lets a user scan the complete hard drive and find the booby traps. I hesitate to recommend this because it presents a user with a long list of items that may not be booby traps.
If you go to
http://forums.spywareinfo.com/index.php?showtopic=227 this may help or use the resources offered and contact computersteve.