The March CTP (community technology preview) of Visual Studio Orcas is now available here. You can either install it (side-by-side with VS 2005) or use via a VPC image. This is the first CTP that contains significant web tools feature enhancements – the new HTML/Webforms Designer,
I’ve seen user reports in several forums, where two instances of Internet Explorer get launched when doing F5, CTRL+F5, or View in Browser in Visual Studio 2005 running on Windows Vista.
If you are encountering this issue, taking the following two steps should fix it:
Install the beta version of the Visual Studio 2005 Update for Windows Vista.