Hold down the Option key and start Bridge.
If this does not help then go to your user library (not root, the one in your user account) preferences folder and find and manual delete the AdobeBridge.plist file and again hold down option key to restart Bridge and again refresh preferences.
If this is still not enough you have to consider to also manual delete the contents of the Bridge Cache folder also. (same user library but in the folder caches/adobe/bridge CS3) and inhere find and delete both the plug in and cache folder outside the library. Preferable in the trash but you can do so later.
After having deleted above mentioned files again restart bridge holding down option key and again reset prefs.
That should definitively work, I used this method a lot when using CS3 because this was (sorry to say) the worst possible version of Bridge.
You will have to rebuild the cache for your files to get accurate thumbs and previews and also your custom prefs settings need to be restored but that just takes a bit of time.