Here's a couple of things to try
A/ ** EASY **
1/ In Internet Explorer click View on the main toolbar and then, from the drop down menu, select Toolbars
2/ On the toolbar list check that there is a check mark next to the Address bar option
3/ Remove the check mark from the address option
4/ If the Address bar appears in the upper right corner and not available, Right Click Address and click Lock Toolbar to remove the check mark
5/ Finally click Address and drag the address bar to where you want it.
B/ ** HARDER **
1/ Click Start
2/ From the Start menu click Run
3/ In the Run dialogue box type: 'REGSVR32 /i BROWSEUI.DLL' (without the quotes) and press OK
4/ Reboot your PC
5/ The address bar should now be back on the main toolbar
Hope this helps
Or even better, dump IE and
Get Firefox !!