Hi Lena and welcome to the forums!
You say you 'have tried everything' but you may have missed something!
There is usually a number of of posts in these forums after any update which, for one reason or another, has caused problems for the posters. A few causes have not yet been properly identified, but the main cause remains the use of third party Input Managers that have not yet been updated to comply with Safari 3.2.1. Some users have reported that switching off the anti-phishing setting in Safari Preferences/Security has stopped their Safari closing unexpectedly, but this of course defeats the main purpose of the update and in any case works perfectly for the majority of users.
Apple cannot possible test for every theoretical permutation of what users have installed in terms of third party software, hacks, plug-ins, what-have-you. The developers of such software can sometimes be slow to update their products to comply with the accepted industry standards that Apple follow (but which others fail to meet), particularly where security updates are concerned.
Nor can Apple allow for what regular maintenance, if any, has been carried out by the user before installation, and that includes having kept their software up to date.
For the vast majority (millions) of users such updates create no problems at all, but that is the last thing a user with problems wants to hear, and I only mention it to reassure you and not to annoy you!
N.B. Safari 3.2 requires the latest version of Tiger (10.4.11) or Leopard (10.5.5) as well as the installation of Security Update 2008-007, to work. You should also update Quicktime to 7.5.5 if you have not already done so.
Never delete Safari, never run it under Rosetta, check your proxy settings*, and don't change the application's name or move it from the top level of the Applications Folder to a sub-folder.
So, following the advice given here:
http://discussions.apple.com/thread.jspa?threadID=1791104&tstart=0
will usually rectify the situation (and most likely have prevented the problems in the first place), and users with these problems are welcome to copy/paste and print this out, for easy reference
next time a system or application update is offered by Software Update.
If you still have problems, try this as well:
Empty Safari's cache (from the Safari menu), then close Safari.
Go to Home/Library/Safari and delete the following files:
form values
download.plist
Then go to Home/Library/Preferences and delete
com.apple.Safari.plist
Repair permissions (in Disk Utility).
Start up Safari again, and things should have improved. If not an archive and install is the only solution towards rectifying your faulty system.
*If you use proxy settings, read the post from Keats2010 here:
http://discussions.apple.com/thread.jspa?threadID=1797417&tstart=0