MS Office and some other 3rd-party apps no longer open

Question

Whenever I try to open any MS Office applications, the icon just bounces briefly in the dock then disappears. It's Office v. X, carried over from my old iBook. It worked fine on my new iMac for a few months, I think until New Year's Eve when I installed Security Update 2007-009.
Since then I've tried uninstalling (or rather deleting, since the included uninstaller also fails to run) and reinstalling from the DVD, verifying the HD in Disk Utility, installing the combined update from download, and moving or trashing the com.Microsoft.Word.plist and so on in my Preferences folder, but the problem remains.
The computer came with an Office 2004 "Test Drive" which also fails to run, and it's also affected a few other 3rd-party applications, but by no means all of them. For instance, Microsoft Messenger runs fine.
I was waiting for the next security update (2008-001) to see if that fixed it, but no dice. Any help would be greatly appreciated.

Answer 1

Like I said, Office X worked fine on the intel for the first couple of months. And the Office 2004 taster which came installed (and so should work regardless) was affected in exactly the same way, so it's not a compatibility problem. Also, repairing permissions is what I meant by 'verifying the HD in Disc Utility'.