EDITED: Sorry about those extra spaces, don't know how they got there, Fixed Now! Thanks to porterkm
Take the default Autorun.inf file from \PortableApps and copy it to \
Default Autorun.inf looks like this:
[Autorun] Open=PortableApps\PortableAppsMenu\PortableAppsMenu.exe Action=Start PortableApps Icon=PortableApps\PortableAppsMenu\PortableAppsMenu.exe Label=PortableApps
Now edit \Autorun.inf so it looks like this:
[Autorun] Icon=PortableApps\PortableAppsMenu\PortableAppsMenu.exe Label=PortableApps shellexecute=PortableApps\PortableAppsMenu\PortableAppsMenu.exe UseAutoPlay=1
Open My Computer, right click on your USB drive letter, click on properties, click the autoplay tab, choose mixed content, and select action to perform, take no action. That should work, but if it doesn't then do the same for every autoplay option in the list.
Some programs change the autoplay options for USB drives, two that I know of are Windows Media Player (turn off sync) and Adobe Photo Album. If you install or update these programs just go back into My Computer and change the autoplay option for your USB back to take no action.
I've done it on XP Home and XP Pro and it worked on both. Let me know how it goes.
PS: I don't know if it makes any difference, but I have formatted this USB in Windows and gotten rid of the sony software it came with. Sony MicroVault 2G, does anyone happen to know if that would make a difference in this process?
XP Home and Pro are both with SP2