Safari 4 installing problems

Ever since I tried updating to Safari 4, I have had a problem. Currently, I am running Safari 3.1.1. After trying to update to Safari 4 a couple of months ago I tried opening up Safari - no luck! I uninstalled Safari 4 by deleting it from the Applications Folder. I then tried installing Safari 4 again - and again Safari 4 wouldn't open. I then used Firefox to go online and search for Safari 3.1.1 so I could use Safari. I didn't mind using Safari 3.1.1 until I updated iTunes to 9.0.2. Now, I can no longer go to iTunes store where I have more than $50.00 left because the iTunes store requires Safari 4.0.3 or later. Can anyone help with this problem? I'm sure when I try to delete Safari 4 - I'm not deleting everything which I should - so that when I try to update to Safari 4 - the computer thinks I already have 4. I've tried locating an earlier version of iTunes - but I cannot find it.

Please help!

seitzteacher@yahoo.com