Trying to install SQL Server Express 2005 on Windows 7 64bit?
You may see issues especially if you are using one of the lightweight downloads of SSE that is dual x86/x64 packaged for x64 WOW.
If you are seeing an ASP registration error, make sure you have the ASP and IIS features ON in Windows 7 – especially the IIS 6 compatibility pieces of IIS.
“cscript %systemdrive%inetpubAdminScriptsadsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 1”
Which should set you right to run SQL Server setup again.
I stumbled on this on a fresh VM of Windows 7 installed today to run a legacy App that uses SQL Server Express 2005 and plucked this line of script out of my SharePoint knowledgebase after 5 minutes of headscratching.
Hope this helps somebody out there.
Enjoy, but remember no warranty expressed or implied and use at your own risk!