found this piece on info on this site, but am unsure what to do with it. don't know what is meant by DWORD.
HOW TO FIX THE PROBLEM OF WINDOWS XP LOSING EXPLORER WINDOW POSITIONS AND VIEW SETTINGS
By default XP only stores Window positions and views for the last 400 folders (or windows) which means that once this is exceeded, new folders will not store their last positions or correct settings. To get round this, run Regedit and delete these two keys :
Then add the following lines which will make the 400 limit increase to 1000 - should be enough for normal use.
Run Regedit, find these two keys:
Add this new DWORD value under BOTH above keys:BagMRUSize (with size 1000 decimal)