Cannot close ie8 in Vista

For some reason we cannot get IE8 to close on a friend's Vista Home Premium laptop. Clicking on the red x produces a ping noise, using task manager under Applications tab doesn't always do it either, though selecting iexplorer.exe in Processes will always do so. Anyone have any idea what could be causing this problem? Or ideas for rectifying? I suspect it may be awaiting input - but I can think of no reason for this to be the case, and no dialog boxes are visible. I've told the poor so-and-so whose machine it is to use Firefox - but he prefers ie.

If it is just a broken application (possibly caused by using Laplink PC Mover to move MS Office 2002 (but nothing else, knowingly) over from an XP desktop, an otherwise highly successful operation) - is it feasible to uninstall then reinstall IE8 without trashing Vista?
David

 

Thanks Pete - Will try, and let you know what happens in a few days when I get access to his computer again.
best
David