I have had my hands full for a few days.
The portable nvda doesn't read the tree view in device manager on windows 7 x64.
Here is a work around:
create a desktop short cut for c:\nvda\nvda.exe
go to properties advanced and check the box run as administrator
u a c keeps coming up but do alt + y and nvda starts.
The tree view in device manager is now accessible using nvda portable.