1) restart the computer
and see whether that resolves this.
2) a different kb article suggests that installing in safe mode might resolve this--I've not attempted that--if you do, and it works, please let us know!
3) this is clipped from a kb article relating to a different product, but the workaround may be more broadly applicable. I would modify step 2 slightly. I would 1) Save that key, and then, 2) delete it.
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Method 2
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
Use this method if you receive the following error message:
Error 1500. Another installation is in progress. You must complete that installation before continuing this one.
1. Click Start, click Run, type regedit, and then click OK to start Registry Editor.
2. Locate and delete the following subkey in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\InProgress
3. Close all windows, and then restart the computer.
4. Install Small Business Accounting from the installation CD.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
