Run the un-installer again. Do a search for anything related to digidesign that may be left and delete them, then run registry cleaner.
Re-install Pro Tools (I assume you have PT version 8) onto system drive (C:) only.
Once installed don't open it. Instead download and run the v8.05 updater;
http://avid.custkb.com/avid/app/self...p?DocId=393667
I vaguely recall Vista needs v8.04 or higher.
Ignore any 'Found new hardware messages' that pop up (they should disappear automatically) and only turn on Mbox when prompted to do so.
However, once you have it installed correctly you may still experience performance issues since your computer looks a little dodgy, for instance;
2GB RAM is bare minimum
Integrated graphics often cause problems
It looks like you only have one HDD.
To run PT properly you need to have it installed on the system drive (C:) and record to separate drive. Recording to a separate partition on the same drive is no good.
Best of luck.