I have Internet Explorer 5.5 SP2 installed on two separate machines. One has the Security tab when I go to Tools, Internet Options and the other does not. How can I get the security tab back?

Try using the IE Repair Option. Start/Settings/Control Panel/Add/Remove Programs. Scroll down to IE 5 or 5.5 and click it to hilite it, click the "Add/Remove" button and choose "Repair Internet Explorer", click "OK". Hopefully this will get your "Security" tab back. Post back with the results.

tried what you suggested Tufenuf and it didn't work. Is there maybe a registry setting to get it back?

You could try a scanreg /restore(space between g and /) by following the instructions below. If it doesn't fix it you will have to uninstall then reinstall IE 5.5 SP2. Here's the instructions and choose a registry date prior to the problem starting(there should be 5 dates). How to Manually Restore the Windows 98/Me Registry no keysno keys---------------------- The information in this article applies to: Microsoft Windows 98 Microsoft Windows Millennium Edition no keysno keys---------------------- SUMMARY This article describes how to restore a backup copy of the Windows 98 or Windows Millennium Edition (Me) registry. MORE INFORMATION Under normal circumstances, Windows is capable of detecting and recovering from registry errors automatically. If Windows is incapable of this, a previous copy of the registry can be restored manually. Windows makes and stores a backup of the registry when you start your computer successfully each day. By default, five previous copies or the registry are stored. To restore one of these previous copies: Start your computer, press and hold CTRL, and then choose Safe Mode Command Prompt Only from the Windows 98 Startup menu. If you are running Windows Me, start your computer with the startup disk. At the MS-DOS prompt, type cd\windows\command, and then press ENTER. Where windows is the name of the folder in which Windows is installed. At the C: prompt, type scanreg /restore, and then press ENTER. Select the previous registry you want to restore, and then press ENTER. NOTE: A properly working registry has the word "Started" next to the date. When you receive notification that you restored a properly working registry, press ENTER to restart your computer. PLEASE NOTE: If you downloaded any new programs after the date of the registry you want to restore it's going to delete their registry entries and you will have to uninstall and reinstall them which could be a nightmare if you have any. It's up to you whether you want to do it or just uninstall and reinstall IE 5.5 SP2.