Lurkr
Are you using XP? I have a P4 2.5gig laptop, 512M ram but it's not entirely happy all the time. Sometimes when I load it up it says "Sorry, Windows Explorer need to close ... blah, blah, please tell Microsoft about this problem." So I do and off goes the report.
Then the screen gets wiped clear of all icons and toolbars and then they come back, BUT it's not a full restart because not all the items in the tray (area near the clock) that are normally there after boot-up return. In fact only a few come back. However, 'puter works ok and seems stable enough in that amended configuration. But to get everything back I have to reboot.
When Windows Explorer hiccupped in 98 and 98SE it usually resulted in a full-blown crash. XP seem better in that regard. But I still don't know the cause.
To return to the topic, none of this results in aberrant TAB, ALT or CTRL behaviour.
AA