4.3.4 killed wifi on Win7 host/VMMRC error post-rollback

[ackthbbft]

This morning I updated from 4.3.2 to 4.3.4, received the usual warning that network connectivity would be temporarily disabled while it installs the VB network driver (as was the case when first installing 4.3.2, my first version), and during installation received a message saying, "A connection with that name already exists," (or something to that effect), after which point the install finished and I could no longer connect to wifi on the host at all (no bars and red x; I didn't test a wired connection, unknown if that was affected), even after rebooting. (Closest forum search came back with the icon being "wrong" with no bars and yellow star with v4.2.16.)

I checked Device Manager, and nothing showed up as being disabled or otherwise not working.

Has anyone else experienced this? Is it better to completely uninstall and reinstall?

I just performed a system restore on the machine, and I am back on 4.3.2 and wifi is working again. Now, however, I can't launch my VM, getting the following error:

The VMMRC.rc module version does not match VBoxVMM.dll/so/dylib.
Re-install if you are a user. Developers should make sure the build is complete or try with a clean build.
(VERR_VMM_RC_VERSION_MISMATCH)

Details:
Result Code: E_FAIL (0x80004005)
Component: Console
Interface: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6}

Not quite clear to me is whether the message is telling me to reinstall the VM (Ubuntu/ElementaryOS) or to reinstall VirtualBox itself. (No forum search match for VMMRC.)