Disclaimer: I do work for Microsoft, but is my opinion. If this walkthrough causes your ferret emotional distress, I'm sorry. Who is this? Stop calling! Jimmy no live here! You no call back!
I'm an early adopter so I've been running Beta 1 of .NET 4 and Visual Studio 2010 on a Vista machine. However, Beta 1 of .NET 4 doesn't survive an upgrade to Windows 7 and leaves the .NET Framework in a goofy and unfixable state. Beta 2 won't have this problem.
So, in a nutshell if you're running .NET 4 and Visual Studio 2010 Beta 1 on Vista you've got two options*.
1. Uninstall, Upgrade, Reinstall
2. Clean Install
When you're talking about OS Upgrades and Early Beta Software, if you really want to be confident, I say clean install.
It an unfortunate Beta 1 bug, so tell your early-adopter developer friends (or blogs) so they don't have trouble upgrading.
* You might be running Windows 7 RC and thinking to do an unsupported upgrade to Windows 7 RTM. If so, remember, it's not supported, but you'll have this problem upgrading too, so uninstall Dev10b1/.NET4 first.
Hope this beta hassle saves you a worse hassle when it comes time for you to upgrade to Windows 7. Again this won't be a problem in .NET 4 Beta 2.
Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, consultant, father, diabetic, and Microsoft employee. I am a failed stand-up comic, a cornrower, and a book author.
You might be running Windows 7 RC and thinking to do an unsupported upgrade to Windows 7 RTM. If so, remember, it's not supported, but you'll have this problem upgrading too, so uninstall Dev10b1/.NET4 first.
Disclaimer: The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.