Internet Explorer 7.
Recently updated machine, though the problem occured a day after.
I seem to recall approving a registry modification in ZoneAlarm, though I do not know what prompted it or what it modified (yes, stupid me).
The command bar has disappeared.
Disabling tabs make it reappear. Enabling tabs make it disappear.
Tabs refuse to work eitherway (cannot open links in new tab, et cetera).
Reinstall only option?