I want to use Revo Uninstaller portable on a USB stick on a friend’s laptop.
How do I use it so there’s so no trace of Revo left behind?
Not sure, as I haven't used Revo in ages, but I can recommend IOBit Uninstaller, which apart from being portable (i.e. there is no "non portable" version), is also a really fine uninstaller.
Revo Uninstaller free do not work on 64bit windows you have to purchase Revo Uninstaller Pro.
I'm using Windows 7 Ultimate SP1 64-bit and it works just fine.
http://www.softpedia.com/get/PORTABLE-SOFTWARE/System/System-Enhancements/Portable-Revo-Uninstaller.shtml or http://portableapps.com/apps/utilities/revo_uninstaller_portable
Just make sure to save the backups on your flash drive instead of the computer's hard drive if you don't want to leave really any traces of Revo Uninstaller being used.