If you are using the July CTP Edition, then SQL Server Express installation
might indicate failure though it has actually succeeded due to a mismatch in
version checking.
Uninstallation of the July CTP Edition, as indicated on the MSDN subscriber
site:
1.. Microsoft Visual Studio 2005 (Professional/Standard/Enterprise
Architect/Team Suite etc. or other related IDE installs)
2.. Microsoft SQL Server 2005 Express Edition
3.. Microsoft SQL Server 2005 Tools Express Edition
4.. Microsoft SQL Native Client
5.. Microsoft Visual Studio 64bit Prerequisites Beta
6.. MSDN Product Documentation
7.. Microsoft Visual Studio Tools for Office System 2005 Runtime Beta
8.. Microsoft Device Emulator 1.0 Beta
9.. Microsoft .NET Compact Framework 2.0 Beta
10.. Microsoft SQL Mobile 2005 Development Tools
11.. Microsoft Visual J# Redistributable Package 2.0 Beta (If you see an
error removing J# Redistributable Package from Add/Remove Programs, please
run "msiexec /x {9046F10C-F5E7-4871-BED9-8288F19C70DF}" from a command line
window)
12.. Microsoft .NET Framework 2.0 Beta (If you see an error removing .NET
Framework 2.0 from Add/Remove Programs, please run "msiexec /x
{71F8EFBF-09AF-418D-91F1-52707CDFA274}" from a command line window)
There is also a Beta Cleanup Tool available but I don't know if it works
with the CTP Editions:
http://go.microsoft.com/fwlink/?linkid=47065