Struggled with this one for 2 days and went through tons of

forums till I found this one:

http://social.msdn.microsoft.com/Forums/en-

US/sqlsetupandupgrade/thread/84b399b5-7d7b-46fa-8f86-

8c9af2cbf641

SokSa.Icy had the right idea.

My particular problem also involved going through the

registry to remove all instances of Visual Studio 2008 as

well as a .Net 3.5 hotfix that I could not get rid of.

Once I uninstalled and did everything this guy did, I also

went through the registry and searched/deleted all

instances of the framework hotfix to get it out of the

add / remove dialog box in control panel.

I also used wise registry cleaner to make sure I got all

inconsistencies out of the way, rebooted, and

installed .net 2.0 Express.

After a successful installation, I rebooted again and ran

sql server 2005 express installation and presto - back in

business...