If you haven't done so already, please do the following actions:
Validate and Supervalidate instructions
First save a backup file prior to performing these steps
Validate:
Super Validate:
Kang! said: No luck... Tried validate AND super validate. Investing tab is still unresponsive
Have you tried restarting your computer after this happens? You may additionally try uninstalling the Quicken software using the steps listed in this Support Article, then deleting Quicken from the Program Files (x86) folder. You may then reinstall the software after following those steps using the steps listed here.