Wrong default pdf program from Internet explorer

Since the upgrade to PDF Creator 2.3, Internet Explorer 11 (Windows 7 Pro 64 bit) now creates a pdf document in Architect 4 rather than in my default .pdf program Adobe Reader.
Architect 4 is not installed on my computer, the Architect 4 controls on the created screen do not work (fortunately I can print after right-clicking the created document), and all the general program defaults seem to be set to Adobe Reader. Architect 4 does not appear in any default settings anywhere.
The created file address is
https://xxxxxxxxxxx.com.au/xxxxxxxxx/AccountsOnline/screenControls/scDownloadablePaymentSlip.aspx” if that helps.
Other .pdf documents open correctly.
Should I just uninstall and re-install? Can I update the defaults from there?