ned found a good link which describes how to run multiple different versions of ie on the same machine. this is a great boon for the web developer as we constantly have to handle the different restrictions that each browser has. for example, a .net system that i am involved with works flawlessly on ie6.0 but as soon as you click a link in ie5.5 it crashes your browser. a simple problem to fix once the offending javascript has been identified but until now we had been running round trying to find machines with the offending version installed.