SSI-Gary,

Reading you post, it does not mention Re-installing Excel 2010 you state that Excel 2010 remains...

I would try re-installing excel 2010.

You can search your registry for this "Excel.Application" and see what version it thinks is there. I think 365 shows up at 15 or 16...

I am thinking something in the registry related to the Excel.Application class is changed to something that is not valid for Excel 2010.

Hope this is helpful,

Kevin

Kevin,. Sorry I forgot to mention this.  I did try a reinstall but it made no difference.   

SSI-Gary,

First have you tried opening excel just to open excel... I do think I remember a strange behavior trying to launch excel from an application having an issue if it has not been launched individually and getting through the activation process first...

if that isn't the issue... 

I would try uninstalling Office then search the registry for       Microsoft.Office.Interop.Excel.Application      

If it is found it will be in a folder like InprocServer32... below that is a folder LocalServer32.

What does it have in the LocalServer32 folder for a path pointing to Excel.exe see if that path exists.

if it does not exist or Microsoft.Office.Interop.Excel.Application is not found that is actually good at this point.

Reinstall Office/Excel 2010.

Then check the registry again for the same info above.

if the path in the LocalServer32 is valid.

Try the excel launching by opening a command prompt changing the directory to the path specified in in the LocalServer32 folder and try running    Excel.exe

Keep us posted,

Kevin

excel is running as a background task. The last step to bring it to the foreground to display is the issue.   

Gary,

If you just launch Excel by itself using the Start Programs shortcut does excel launch and display?

Kevin

Yes.  Excel launches normally.   

I would try support and see if we can get a dial in set up to look at this to try to get this resolved so you don't have to start on a clean OS.

Kevin

The issue was urgent.  I tried multiple installs, uninstalls.   Eventually found Microsoft had a Microsoft Office Scrub tool which deleted all traces of Office.    That resolved the issues.   Seems like there are some registry entries that are kept even after a regular uninstall.  

Great glad you got it resolved!

Kevin