I discovered that, those pesky screen blanking intervals that occur when ever UAC is triggered are caused by an interaction between "Desktop Composition" and the "Secure Desktop" element of UAC.

Either unenabling "Desktop Composition" or Disabling "Secure Desktop" will make the multi second screen blanks surround UAC dialogs go away. Vista will simply darken the background, and bring up the UAC prompt. Just what it should be doing.

Disabling Secure Desktop is not good, Secure Desktop prevents background tasks from interacting with the UAC dialog.

Desktop Composition is responsible for the translucent glass look of Vista Aero. Setting your theme to Aero Basic or Windows Classic also disables Desktop Composition.

I stumbled on all this while doing a clean reinstall of Vista Ultimate and the machine initially came up with a vanilla VGA driver that didn't support the translucent effect, AND didn't have those annoying blanking intervals.

edit: P.S. Turning off Desktop Composition boosted my Windows Experience score from 2.4 to 3.0.

I've used Vista for approximately 5 minutes total, but maybe you need an updated video card driver or maybe just an updated video card?

I'm with Bitt. I never got screen-blanking problems with UAC enabled. At the default settings, it behaved as you say it should behave, with the screen merely dimming and the dialog box showing. I believe Bitt is right and that the true problem is in the video drivers.

This is all with the latest driver. Only available from HP. Nvidia's driver for the GeForce Go 6150 refuses to install, claiming that it finds no eligible devices.

What Bitt said. It is a driver issue when you get that problem.

If it is a laptop chipset then you'll either need to hack the official drivers to accept your chipset or find one of the many hacked variants out there already.

Yup, what Trevor said. Despite the fact that you've got the latest video drivers, it doesn't mean you've actually got the latest video drivers.

More detail:

I was having trouble with my laptop, problems with multiple monitors, docking and undocking, and sleep/wake. It just so happens that the laptop was also an HP model.

Even with the latest HP-supplied video drivers, I was still having the problems. One of the problems I knew (from release notes) was specifically solved by a new driver from the video chip manufacturer, but that version of the driver had not been packaged by HP yet and was not available through HP.

See, the laptop manufacturer doesn't repackage the drivers for their laptops immediately after the video chip manufacturer releases a new reference driver. There is often a long lag period and sometimes the laptop manufacturer never gets around to a release. And because the laptop and video card manufacturers have worked out deals where the video card people don't want to have to support all the laptop owners, they deliberately cripple the reference drivers so that they won't install easily on the laptops, and you're forced to go through the laptop manufacturer for support. I find this an awful, irritating practice, and I'm pretty sure you've just run afoul of the same practice.

In any case, installing the latest reference driver via one of the methods mentioned in this thread completely fixed all the problems I was having on the laptop. I was angry that I actually had to *hack* a video driver installer to fix my problems, but now that I've done it, I'm a happy monkey.

My issue was with ATI drivers, but I'll bet it's exactly the same with the Nvidia drivers in your case. Have a scrape 'round the net for utilities that will let you hack reference drivers onto laptops.

There is a security setting that turns off the annoying screen blackening when a UAC prompt comes up. That might be an easy way to solve your problem (which I suspect is the drivers).

Right, he's saying that the security setting to which you refer opens a security hole, and he'd prefer not to change that setting. I agree: He shouldn't have to change that setting. His video driver simply shouldn't be turning of his monitor each time a UAC prompt pops up, that's just a bug.

http://funjs.spaces.live.com/blog/cns!6706B49CFB9415E9!271.entry

After searching for nvidia hacks with 6150, I found the above.

Had exactly the edits needed. Now to reboot...

Edit: Came back up fine but the nvidia driver does no better.
It was dated 10.7.2008.

I wonder if maybe the screen shift to secure desktop uses some sort of GPU accelerated feature that the 6150 doesn't support. Just a random guess, as my only experience with UAC has been to turn it off, to avoid the broken mess it causes to my Wintendo disk due to the admin and virtualazation bits.

As mentioned it seems to be a problem related to Desktop Composition.

That feature of aero is what lets the translucency work. Each window is rendered into it's own bitmap with Alpha channels. Desktop composition is what does all of the layering of one bitmap on the other.

The 6150 seems to operate the same with desktop comp on or off. It's just that as it shifts into Secure Desktop, there is a 5-6 sec blank screen delay, just before the dimming effect takes place.

It shouldn't do it however. The problem is with the drivers or the actual chipset itself.

I've got an 8800 in my desktop PC and for a couple of driver versions it did what you're talking about. It wasn't quite as long as 5-6 seconds but there was a noticeable delay. The problem went away when I next upgraded the drivers.

UAC. Unamerican Activities Committee?
Does that mean that Microsoft must report you if you are a "fellow traveler"?

I didn't realize it had once again come to this....

Maybe the tide will ebb once again with the change in administration.
...or maybe we'll just spy on a different subset of people.

I was more thinking it was Union Aerospace Corporation where nobody has any duct tape.