You are trying to reinstall Internet Explorer, but the following error messages are displayed:
Setup has detected a newer version of Internet Explorer already installed on your computer.
Setup can not continue.
Use the System File Checker tool to analyze the system files and check for errors.
Go to menu Start and select Run,
then type the following command, and confirm by OK:
sfc /scannow At some point the system may ask you to provide the installation CD of Windows XP or Windows XP Service Pack.
Check if Internet Explorer is working properly, in the other case move the below steps.
Editing the registry
Open the registry as administrator.
Depending on the version of Internet Explorer, search the appropriate registry subkey, right-click on the IsInstalled (REG_DWORD) value and then click Edit.
To reinstall Internet Explorer 6 on Windows XP, use the following registry key: