The profile for Firefox is personal to you, and gets picked up by whatever version you use. Even if you uninstall Firefox, the profile, and program folder, remains. Removing that profile and program folder gives you a clean install, by removing all addons and other information Firefox keeps just for you.
Let's try a clean uninstall. Please click here
for instructions at the Mozilla site for removing Firefox.
The important part to the clean uninstall in this case is removing the user data and settings after Firefox has been removed, so please complete all of the instructions for Windows XP 32 bit.
If you run into any snags, especially with removing your user profile (in C:\Documents and Settings\Carolyn\Application Data\Mozilla\Firefox\), let me know and I can help you.
After you have completely removed your profile, you can reinstall Firefox's latest version, and let me know if it still crashes on start-up.