Did you by any chance click on an old v1.5.0 shortcut to start SmartSDR?
That would force the downgrade.
It sounds like the FlexControl got fouled up by doing a forced downgrade install, then the reinstall of v1.5.1.
This link may help.
You might need to use the correct full uninstall procedure, to get it correctly installed at this point. In which case this link might help.
73, Jay - NO5J
If you don't uninstall previous versions it is all too easy to confuse the life out of yourself! New versions create new icons, but if you also have start-menu or task bar icons too, then these do not get updated. Therefore it is all too easy to click the old versions' icon and end up being asked to "downgrade" (to get the old version working). I've done that mistake a couple of times now, and thus always make sure old versions are completely removed first.
Not sure why the flexcontrol won't work after re-upgrading, but I'd suggest a full removal of all versions, then a reboot, then a re-install 1.5.1 should sort it.
Cheers, Steve G1XOW
I suspect that you have a USB COM device conflict as a result of the install/reinstall process.
Open the Device Manager and find the COM & LPT devices entry. You should find an entry in that list for the FlexControl. Click on the item with the right mouse button and select properties. On one of the tabs you will find an Advanced button - click on this and you will be able to reassign the COM port number for the FlexControl.
There is a detailed guide to how to do this here: