I’ve found when you install those multiple ie things they don’t always work.
eg: running IE6 when IE7 is installed means that none of the IE6 conditional code will parse, because it thinks it is IE7 , it just runs like IE6 . its basically IE7 with no PNG support hehe
the fool proof way is to have 3 windows installs, each with a different version of IE installed (which sux). I’ve left one computer running IE7 , another running IE8 , and a virtualbox setup for IE6 plus all the other crap that doesn’t run on my laptop.