My understanding is that if I update to IE8 I won't be able to retain IE7 and the IE7 rendering mode in IE8 isn't exact. I want my sites to appear as I intend in both. Anyone know how I can run both IE7 and IE8 on the same machine? Do I need a virtual machine? If so, where can I get one (preferably for free) or at least what terms should I google?

(If there's a better section of these forums for posting this question, just lemme know!)

Thanks so much!