Unable to uninstall items in Programs & Features

I right-click an item in the list of Programs & Features but no context
menu is displayed so that I can not uninstall the item(an application
program). How can I unistall it?

I have exact the same problem in Programs & Features. in the subtab
installed updates, the remove button *_does_* appear & there is an
context menu when right click.

I think the cause of this is a corrupt uninstall of Zone Alarm (this
was executed via Programs & Features): while uninstalling zonealarm the
uninstallprogram didn't respond anymore, though ZA was correctly
uninstalled. So it stayed open. (note: the uninstallprocess was a *.temp
process, it could not be ended)

OS: Vista Home Premium sp1 32bit


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Bouncing Bullet