By now you've probably found a workaround, but for reference:
If you want to get hacky you could always modify the msi installer using a tool like Orca (as mentioned in the section "Step 2: Upgrade to EPiServer CMS 5.2" in this blog post: http://tedgustaf.com/blog/2011/3/upgrade-an-episerver-cms-461-to-episerver-cms-6-is-not-without-bumps/)
Otherwise you're pretty much stuck with installing on another machine (try using VirtualPC or similar).
I'm trying to install CMS 5 R2 on my machine. I'm getting an error when I'm running EPiServerCMS.msi. I'm running only this, since it's not possible to install multiple instances of EPiServerShared.
I'm currently running Windows 7 with SP1
I'm getting this error message:
The installation is not supported on this version of Windows. The following version are supported:
Windows XP with Service Pack 3
Windows Server 2003 with Service Pack 2
Windows Vista with Service Pack 1
Windows Server 2008
Is it any way to bypass this or do I need to install the software on another machine?