Previously I was using Tredosoft's Multiple IEs for years, running XP with IE7 native. A quick tip - installing the same program on a Windows 7 machine will wreck your registry and require a "Back Up & Restore". Tredosoft's Multiple IEs doesn't work in Windows 7 so the solution immediately goes to a choice between Virtual PC (400MB+ download from microsoft.com) using "XP Mode" in Windows 7 and running IE7 + Tredosoft in the virtual environment for testing purposes only, or go with VMware player and do the same thing. Craig Buckler wrote a good article on setting up through the Microsoft route on sitepoint:
"Virtual PC is Microsoft’s alternative to VMware and VirtualBox. It’s available as a free download for most versions of Windows. As a standalone product, it’s functional but offers fewer facilities than the competition. However, XP Mode is Virtual PC’s killer feature. It provides:
- a fully licensed, stripped-down, virtual copy of Windows XP SP3.
- a clever facility which integrates the guest Windows XP OS with your Windows 7 host. In effect, you can run XP applications as if they were native Windows 7 programs. Although the XP application is isolated, it can still access the host’s files and systems.
Source: http://articles.sitepoint.com/article/ie6-ie7-ie8-win7-xp-mode
Download: http://www.microsoft.com/windows/virtual-pc/download.aspx
Tip: For Cross-browser CSS testing required by web design - RunXP in virtual mode with IE7 and Multiple IEs, recommended to use VMware Player.
Multiple IEs: http://tredosoft.com/Multiple_IE
"VMware Player is the easiest way to run multiple operating systems at the same time on your PC. With its user-friendly interface, VMware Player makes it effortless for anyone to try out Windows 7 or the latest Linux releases, or create isolated virtual machines to safely test new software and surf the Web."
VMware Player: https://www.vmware.com/products/player/
Virtual Box - Open Source Solution: http://www.virtualbox.org/wiki/Documentation
Untested - "Final Builds" Site: http://finalbuilds.edskes.net/iecollection.htm