Temporary use of Aero even when deactivated?

Hi folks, I have disabled Vista's Aero to speed up my system but

yesterday I accidentally hit a combination of keys when alt-tabbing

through my open windows and the Aero thing briefly kicked in where I

could see all my open windows in the 3d style stack. But now I can't

replicate that same combination and was wondering if it's a known

thing that someone can share because that was the one aspect of Aero

that I actually found useful.

In its absence till now I've been using a freeware app called

Freewheel that allows me to scroll back and forth through my open

windows using my mouse's scroll wheel. I'd uninstall it if I could

figure out how to turn on the Aero thing again.

Any suggestions?

Thanks in advance,

Jo