No application can be installed - stuck at 0% forever

My company recieved a set of seven Dell D630 laptops with Vista Business preinstalled.

I set one up for XP Pro (which, despite the headaches of actually getting the thing set-up for XP, worked well - the manufacturer did not make it very easy - likely to benefit a certain company and their new "Vista" of what an operating system should be).

The remainder were for IT folks - management felt Vista on these machines would be a good way of familiarizing ourselves with it.

Management has no idea what a time suck this process has been.

Believe me, after setting 75-80 Vista machines up with this operating system I'm familiar with it as I ever want to be.

But I've NEVER had such an infurating experience as I have today.

For the first time I have a Vista system that will not install software
applications (Office 2003, Office 2007, Wyldfyre Listings, Windows
Update, etc.) It would simply freeze the progress bar at 0%
as long as you wanted to wait.

So, I've played around with permissions, administrative rights,
shutting off the UAC, enabling network discovery, trying different
accounts, modifying firewall settings in case it was a network issue.

I thought it was nearly every app but I tracked it down using
Problem Reports and Solutions. It reported something
unusual:

It claims that InstallShield setup launcher isn't compatible with Vista (which doesn't make any sense since so many apps use it) and will
do the following upon launch:

Goes thru the motions of being set-up, then:
At the first sign of a progress bar, the machine sits at 0% as long as you care to let it go. Hours if you want.

Is there any way around this - I was on the verge of reimaging this
disaster and I still may. Has anyone else experienced this? Of course,
there's no solution to this according to the information Problem Reports
and Solutions indicates.

Thanks for any assistance you can provide.