This Microsoft KnowledgeBase Article
discusses PAE and Vista.
Supposedly, you can enable PAE in Vista by running "BCDEdit", the boot configuration editor that is included in Vista. You should run this in "administrative mode".
Typing "cmd" in the "start" "search" space, and press Ctrl + Shift + Enter. This runs "cmd" in Administrator Mode.
Then type - "run" Type - BCDEdit /set PAE forceenable
Of course, if your system didn't meet the requirements shown in that KnowledgeBase article, it won't work.
Let us know if this helped, OK?
Oh, it appears that "BCDEdit /deletevalue PAE" should remove the command, again, at the Admin level.
Edited by JohnWho, 27 May 2007 - 02:03 PM.