Install of 2005 tools fails

I'm trying to install SQL Server 2005 tools, but keep getting this error,

TITLE: Microsoft SQL Server Setup


None of the selected features can be installed or upgraded. Setup cannot proceed since no effective change is being made to the machine. To continue, click Back and then select features to install. To exit SQL Server Setup, click Cancel.

For help, click: http://go.microsoft.com/fwlink?LinkID=20476&ProdName=Microsoft+SQL+Server&ProdVer=9.00.1399.06&EvtSrc=setup.rll&EvtID=SQLSetup90&EvtType=28108

Then on the Details, it says the following,

Name: Microsoft SQL Server 2005 Tools
Reason: Your upgrade is blocked. For more information about upgrade support, see the "Version and Edition Upgrades" and "Hardware and Software Requirements" topics in SQL Server 2005 Setup Help or SQL Server 2005 Books Online.

Build version check:
Your upgrade is blocked because the existing component is a later version than the version you are trying to upgrade to. To modify an existing SQL Server component, go to Add or Remove Programs in Control Panel, select the component you would like to modify, and then click Change/Remove.

I uninstalled the Express tools from the system and can't get the tools to install. I've rebooted to no avail. Help!After installing/uninstalling the Express product a few times, I found a solution: I ran the Install Cleanup utility (http://support.microsoft.com/default.aspx?scid=kb;en-us;290301), and removed any references to SQL Server 2005. Then I went into the registry (PROCEED WITH EXTREME CAUTION HERE!) and deleted the services that had been created for SQL Server 2005 in HKEY_LOCAL_MACHINE/SYSTEM/SERVICES. Then I found the install folders (from the service registry keys above) and zipped up their contents and moved them elsewhere, deleting the original files. In between, I ran two different registry cleanup programs, which found issues and resolved them. One is a free tool, called RegScrubXP (do a Google and it should come up).

I also generated an MSI Inventory using a special tool described here to ensure that SQL Server 2005 was nowhere to be found: http://blogs.msdn.com/astebner/archive/2005/10/30/487096.aspx.

You've got to also remember that there's an order in uninstalling the items: You remove the db first, then the tools, then the support files, then the native client. Please correct me if I'm wrong on this.

After about a week of wrestling with it, I've removed the express tools and finally got the full SQL Server 2005 client tools installed and am very happy