If you would install Firefox on the D:/ drive the vast majority of its files would end up in /Documents and Settings/ on the C:/ drive where the operating system resides.

Firefox Portable will keep all its files together, where you install it. http://portableapps.com/apps/internet/firefox_portable

I installed Firefox Portable on a memory stick in F:/drive along with Adobe Flash Player plug in. Thank you for your advice, it seems to work fine. I need help on two more related items:

i) I only chose the Mozilla Firefox Portable app during installation.
   Can you show me how to bring this long list of available apps up on the  monitor and how to install any additional apps.  Can Firefox run more than one app at a time eg. Firefox Portable and Audacity?

2) I want to have Mozilla Firefox Portable as my browser. But I need your help to show me how to make Google as the default search engine to minimize the number of steps required to bring Google up as the search engine Thank you

You can install the regular release on the D drive, but you would have the use the Profile Manager to create a profile on that D drive by choosing an empty folder for that new profile. Never use a folder that already has files in it.

• http://kb.mozillazine.org/Profile_Manager

See "Creating a profile":

• https://developer.mozilla.org/Mozilla/Multiple_Firefox_Profiles
• https://developer.mozilla.org//Mozilla/Multiple_Firefox_Profiles#Creating_a_profile

• http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows
• http://kb.mozillazine.org/Shortcut_to_a_specific_profile
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox