(Default) instance already exists (not really!)

Ok,

I haven't had this much trouble installing MS software in many moons. My end goal is to install Team Foundation Server, but to do that I need SQL Server 2005 first, then SharePoint, then TFS. At each of these steps it is appearing to be a mine field, and it is apparent that the MS Installer is doing a terrible job at uninstalling everything.

End of whine. So my situation is this, I had installed MS SQL Server Developer 2005 and found out that the Reporting Server wasn't working. Basically, because at one time or another I had FP extentions installed, and permissions were hopelessly munged. The fix on the forums was to back everything out... SQL Server, IIS, Sharepoint, and do a scorch and burn, effectively erradicating any trace that any of these existed on the disk.

This accomplished, but... now when I try to reinstall SQL Server, it claims the default instance "already exists." So... I've tried various registry hacks, tracking down any trance of instances. Here are some of things I've tried to no avail...

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=148487&SiteID=1
http://support.microsoft.com/default.aspx?scid=kb;en-us;290991&sd=tech
http://support.microsoft.com/default.aspx?scid=kb;en-us;290301

So... short of going beyond scorch and burn, and nuke the entire machine, what are my options? Erasing the OS and starting from scratch does not seem like an option because, it seems, that seems I'll never get anything installed if I have to keep doing this.

Ideas anyone? Your help is greatly appreciated.

-Eric

FYI -- When running RegSeeker I find nearly 300 bogus registry entries left over from the MS uninstall--someone's got to fix that.Ok, I found a possible solution. But... it is very very risky. So don't blame me if you torpedo your server using my advice. But it worked for me.

But I'm posting this in case someone else find themselves in the same bind as me.

Following the suggestion of one of the other forum posts I saw, I looked for all entries for SQL Server. I saw a zillion entries for version 9.0.242.0.

Using RegSeeker, I wacked those. So they were gone.

Next, I saw another bazillion entries for "SQL Server." I surmized that SQL Server was completely uninstalled, these should be gone as well. So I delete those as well.

Another search for "SQLServer" also turned up a bazillion entries. Most of these were classes. Taking a deep breath, I deleted all of these as well.

In all, there were many thousands of registry entries that probably should have been deleted by the uninstall, but weren't.

So far, I've managed to reinstall SQL Server 2005 Developer and all is A-OK. So problem solved (I'd knock on wood if I have any real wood in my cube).

-Ericsql