First of all open up the command prompt. For that go Start -Run - cmd. Now press CTRL + ALT + DELETE to bring up the task manager. In the task manager, go to processes and click on explorer.exe. End the “explorer.exe” task. All the windows will be closed down. Don’t panic. You can still see the command prompt. In the command prompt type the following command exactly as it is:
Del "C:\Documents and Settings\<your_log_in_name>\Local Settings\Temporary Internet Files\Content.IE5\index.dat"
Note <your_log_in_name> is the name that you use to log in to your windows. Some log in as “administrator” while some with another name eg: Sandeep. Whatever it is, type that name. This will also help in fixing all the issues related to browser performance, especially the ones that cause browser to hang frequently.
"Windows XP Tips: Delete INDEX.DAT "Faster Browsing""
Reference : techpraveen.com