Ubuntu 18.04 LTS: Manually uninstalled Virtualbox and now can’t install again

I recently installed Virtualbox, but I accidentally did not sign the kernel modules while installing. This resulted in Virtualbox running, but unable to run a vm. First, I tried signing the kernel modules according to directions here: https://superuser.com/questions/1438279/how-to-sign-a-kernel-module-ubuntu-18-04, but Virtualbox still did not work. dpkg showed an error every time i used apt-get and it…

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