Virtualbox Failed to load VMMR0.r0 (VERR_LDR_MISMATCH_NATIVE)

Computer got hard rebooted with an active guest and ever since I cannot get VB to work. Reinstall, uninstall, scrounge every VB file I can find on the hd and delete, clean update to new version. To be clear all guests, even new ones after the old ones have been completely destroyed, generate this error when I try to start them.

Windows 7, 64. using latest version of VirtualBox (only like a day old).

Here are some logs from log files I found. None of them seem particularly interesting.

00:49:14.833945 ERROR [COM]: aRC=VBOX_E_INVALID_VM_STATE (0x80bb0002) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={Machine} aText={Machine is not locked for session (session state: Unlocked)}, preserve=false
00:49:21.780590 ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={3295e6ce-b051-47b2-9514-2c588bfe7554} aComponent={ExtPackManager} aText={No extension pack by the name 'Oracle VM VirtualBox Extension Pack' was found}, preserve=false
00:49:21.851599 ERROR [COM]: aRC=VBOX_E_IPRT_ERROR (0x80bb0005) aIID={480cf695-2d8d-4256-9c7c-cce4184fa048} aComponent={SessionMachine} aText={Saved screenshot data is not available (VERR_NOT_SUPPORTED)}, preserve=false

00:47:41.904773 UIMediumEnumerator: Machine (or snapshot) event processed, ID = 5a8e9544-e6e0-49cf-8a80-3d6b5b3ab6d3
00:47:44.732378 ERROR [COM]: aRC=E_UNEXPECTED (0x8000ffff) aIID={12f4dcdb-12b2-4ec1-b7cd-ddd9f6c5bf4d} aComponent={Session} aText={The session is not locked (session state: Unlocked)}, preserve=false
00:47:56.420284 ERROR [COM]: aRC=E_UNEXPECTED (0x8000ffff) aIID={12f4dcdb-12b2-4ec1-b7cd-ddd9f6c5bf4d} aComponent={Session} aText={The session is not locked (session state: Unlocked)}, preserve=false