If you have your Windows XP installation CD-ROM, there are a few measures you can try to repair the system files. Since Internet Explorer is a part of the Windows XP operating system, you may be able to fix the problem without having to re-format the hard drive and reinstall the OS.
First try running the chkdsk routine to attempt to identify and repair any corruption there may be to the NTFS file system.
You will need to run the command from the Command Prompt.
Start >> Run >> cmd.exe >> [Enter]
Once the Command Prompt has opened, this command usually does the trick (you need to type it in the command prompt and then press [Enter]):
chkdsk /f/r
It will respond and ask if you want to run it the next time the system reboots, simply type [Y] and press [Enter] to accept and run at reboot. Then restart your computer. It will run the chkdsk command and attempt to locate any disk errors, lost sectors, damaged files, and repair them.
Once the chkdsk routine has completed, try logging in and opening up Internet Explorer and working with it to test it. If you are still noticing slow performance or the program locks up, you can try the system file checker program. NOTE: You will need the Windows XP installation CD-ROM for this.
Insert your Windows XP installation CD-ROM. Open up the Command Prompt and type the following (press [Enter] after entering the text):
sfc /scannow
The Windows File Protection routine will run, which will check to ensure that the correct system files are present and if any are corrupt, it will replace them with the correct ones from the installation CD-ROM.
Once the sfc routine has completed, check the Microsoft update site to download and install any available critical updates - this will include an update for Internet Explorer 7.0. You will want to install all available updates for security reasons, and I would advise upgrading to Internet Explorer 7.0 as well. Once you have installed the updates and upgraded to Internet Explorer 7.0, test it.
http://update.microsoft.com/microsoftupdate/
As many updates will require a reboot, you may need to visit the Microsoft update site twice or three times to download and install all critical updates.
If you are still having issues after the chkdsk, sfc, and updates, a re-format and clean installation may be necessary. If you decide to go that route, I would advise against reinstalling the AOL software and utilities as they tend to bundle additional programs (i.e. Spyware Zapper) which will consume Windows XP resources and slow down performance. If you are on broadband service from your local cable or telephone company, AOL is probably not necessary for you to use - you can still access your AOL email and install AIM from AOL.com.