Anwer
This method assumes that your action may have affected your system files, so
Method 1: Reinstall or Repair Windows XP
To repair or reinstall Internet Explorer and Outlook Express in Windows XP, complete the following procedure while you are logged on as an administrator:
1) Use the System File Checker tool to scan all of the protected files on your computer:
a) Click Start, and then click Run.
b) In the Open box, type sfc /scannow, and then click OK.
Note that you may be prompted for the Windows XP or Windows XP Service Pack 1 installation media.
2) Test to determine if the issue is resolved. If the issue is resolved, skip the remaining steps. If the issue is not resolved, continue to the next step.
3) Complete an in-place upgrade of Windows XP, a repair of Windows XP, or reinstall Windows XP. For additional information about how to complete an in-place upgrade or repair of Windows XP, click the article number below to view the article in the Microsoft Knowledge Base:
315341 How to Perform an In-Place Upgrade (Reinstallation) of Windows XP
(
How to perform an in-place upgrade (reinstallation) of Windows XP)
4) To reinstall Windows XP updates, visit the following Microsoft Windows Update Web site:
Microsoft Windows Update