According to the DigiDesign website:
QUOTE:
Although Windows Vista Home and Home Premium Edition have not been tested or qualified by Digidesign, there are currently no known issues with Vista Home and Home Premium 32-bit operating systems and Pro Tools M-Powered 7.4 compared to the supported Windows Vista Business or Ultimate Edition operating systems.
Windows Vista SP1
There are currently no known issues with Service Pack 1 for Windows Vista based on our initial limited testing and customer feedback. Although full qualification with all Digidesign products has not been completed, we do not recommend against updating to SP1, given the number of important overall system fixes in SP1. We do recommend that you backup your system and create a restore point before updating to SP1, should you encounter any problems after installing the update.
The rest will depend upon the components in your laptop (which you did not specify). For more information check out this page on Digi's website:
Is my PC compatible with Pro Tools on Windows Vista?